How Much Vitamin D Do We Need?


Do we get enough vitamin D for good health? Many people are vitamin D deficient, and what’s more, there’s evidence that the amount of vitamin D in supplement form that relieves deficiency is greater than previously thought. How much vitamin D do we need?

The big vitamin D mistake

The big vitamin D mistake is that health authorities, in particular the Institute of Medicine, greatly underestimated the amount of supplemental vitamin D that will make someone vitamin D sufficient, or to keep that person sufficient.

The Institute of Medicine calculated that 600 IU of vitamin D daily would keep most (97.5%) people at a vitamin D blood level of greater than 50 nmol/L, which in more familiar units is 20 ng/ml. However, their calculation was shown to be a mistake.

Without going into all the details (which you can read in the paper), the authors calculated that 8895 IU of vitamin D daily would be needed to get most people above the 50 nmol/L limit. Huge difference. The authors also state, “As this dose is far beyond the range of studied doses, caution is warranted when interpreting this estimate. Regardless, the very high estimate illustrates that the dose is well in excess of the current RDA of 600 IU per day and the tolerable upper intake of 4000 IU per day.”

A different group of scientists confirmed that this estimate was in the ballpark, with  about 7000 IU of vitamin D daily, from all sources including the sun, needed to achieve 50 nmol/L in most people.

A meta-analysis of studies on vitamin D and mortality showed an inverse correlation between vitamin D blood levels and death rates. See chart below. At vitamin D levels that indicate clear deficiency, death rates were almost twice as high as when blood levels were normal.

The meta-analysis found that the point at which higher levels were no longer associated with lower death rates with statistical significance was 36 ng/ml, or about 90 nmol/L. Assuming this analysis is correct, people should strive for blood levels at least that high. That’s about 80% higher than what the Institute of Medicine recommended.

A pediatrician, Dimitrios T. Papadimitriou, calls the calculations of the Institute of Medicine the Big Vitamin D Mistake. He writes:

Since all-disease mortality is reduced to 1.0 with serum vitamin D levels ≥100 nmol/L, we call public health authorities to consider designating as the RDA at least three-fourths of the levels proposed by the Endocrine Society Expert Committee as safe upper tolerable daily intake doses. This could lead to a recommendation of 1000 IU for children <1 year on enriched formula and 1500 IU for breastfed children older than 6 months, 3000 IU for children >1 year of age, and around 8000 IU for young adults and thereafter. Actions are urgently needed to protect the global population from vitamin D deficiency.

Note that these amounts of vitamin D are from all sources put together: sun, food, and supplements.

A review on vitamin D intake concluded that the maximum safe dose, or Tolerable Upper Intake Level, is 10,000 IU daily. That doesn’t necessarily mean that this is the best dose, but that no toxicity has been seen in human clinical trials at that dose. Higher doses of vitamin D can be toxic. In contrast, the Endocrine Society recommends an upper limit of 4,000 IU daily.

Vitamin D toxicity appears to be rare. The media recently reported on a study on vitamin D usage and misinterpreted it to claim that it’s dangerous to supplement with vitamin D.


Low blood levels of vitamin D are associated with higher death rates.

The amount of vitamin D needed to attain levels associated with better health have been underestimated.

The only certain way to know whether you have adequate vitamin D is through a blood test.

Getting vitamin D through sun exposure is the best way to get enough vitamin D, one reason being that sun exposure has other benefits. But as we saw above, for many people, there’s not enough sun to increase vitamin D blood levels outside the summer months.

PS: I discussed vitamin D in my book, Best Supplements for Men.

PPS: Check out my Supplements Buying Guide for Men.

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Strong Bones Improve Brain Function and Slow Aging

Strong bones are usually thought of in the context of osteoporosis, the pathological thinning of bones in old age. Osteoporosis can be fatal, since it leads to hip fractures, a large fraction of which lead to death within a year.  New evidence is coming to light that bones are an endocrine organ that secretes hormones that are vital for health, and that strong bones improve brain function and slow aging.

Bone osteocalcin affects brain function

Bones secrete a hormone called osteocalcin, which helps to build bone by stimulating osteoblasts, the cells that build bone. Remarkably, osteocalcin also regulates metabolism and increases insulin sensitivity. Mice that lack osteocalcin are insulin resistant and glucose intolerant. In humans, increased bone mineral density leads to higher osteocalcin and lower insulin.

Even more remarkably, osteocalcin is both necessary and sufficient to restore or maintain exercise capacity in mice. Mere injections of osteocalcin increased exercise capacity in young mice and restored it in old mice, giving the old mice the same exercise capacity as the young. Wow.

I see a future for osteocalcin in anti-aging. More on that below.

Regarding the brain, mice that are deficient in osteocalcin exhibit anxiety-like behaviors and impairment in cognitive function. “These results indicate that bone remodeling is a determinant of brain function.”

To show that osteocalcin could improve brain function in older mice, scientists injected it into the brains of old mice. Injected osteocalcin resorted cognitive function.

Here’s where it gets really interesting.

Osteocalcin, the rejuvenating factor in young blood

Osteocalcin declines with age, and is thought to be behind not only the changes in bone with aging, but, as seen in the above-cited studies, many other functions including increased insulin resistance and decreasing muscle mass.

Now, it’s known that young blood injected into older animals has an anti-aging effect. (Although, it must be said, old blood injected into young animals seems to be worse for the young animals than young blood is beneficial for the old.) A start-up company has been transfusing blood from young people into older people. The nature of the factor(s) in young blood that cause rejuvenation have been elusive.

Could the young blood factor be osteocalcin?

In the same study in which scientists injected osteocalcin into old mice, they injected plasma from young mice into older mice, and this significantly alleviated cognitive deficits. Plasma from other old mice did not.

Plasma from young osteocalcin knockout mice, which contains none of the hormone, had no effect either.

Plasma from wild-type mice which had been depleted of osteocalcin (using antibodies) also had no effect.

Plasma from osteocalcin knockout mice that had been spiked with recombinant osteocalcin did increase cognitive function. Ergo, osteocalcin is at least one of the factors in young blood that causes rejuvenation.

The investigators state, “Together, these experiments indicate that OCN [osteocalcin] is a necessary contributor to the beneficial effect of plasma from young WT [wild-type] mice on hippocampal-dependent memory and anxiety-like behaviors in older WT mice.”

It seems likely that recombinant osteocalcin could be used to rejuvenate humans. No necessity for transfusions from young people. Weekly injections, similar to that for testosterone therapy, might work. Once manufacturing scaled up, there’s no reason it wouldn’t be cheap too.

Osteocalcin and iron

High iron stores can decrease osteocalcin, at least in obese people. This could be partly responsible for the decline in osteocalcin seen with aging.

In humans, serum ferritin (which represent body iron stores) were positively associated with glucose, insulin, and insulin resistance, and were negatively correlated with osteocalcin. The effect of iron on osteocalcin may partly mediate the effect of iron on insulin resistance, and could explain at least in part why insulin resistance increases with age.

Osteocalcin and testosterone

Osteocalcin stimulates the production of testosterone.

The relation between osteocalcin and testosterone is not small either, at least in growing boys, with a correlation of 0.57. The association of the two hormones in the general population makes osteocalcin into an indicator of overall male health.

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How to maintain and increase osteocalcin

To maintain and increase osteocalcin, exercise that’s intense enough to make bones stronger is necessary.

Acutely, aerobic exercise increases osteocalcin. In this study, doing leg presses did not increase it as much, though I wouldn’t expect it too unless it were intense and/or long enough.

A longer-term study, in young men, used resistance training and looked at osteocalcin and other markers of bone formation. See chart below. This accords with the well-known effect of weight-bearing exercise on making bones strong.



Bones produce osteocalcin during remodeling and growth. This hormone is only now beginning to be understood.

Osteocalcin has profound beneficial effects on brain function in lab animals.

Osteocalcin increases insulin sensitivity, and is at least partly responsible for the rejuvenating effect of young blood. Recombinant osteocalcin, which could be injected, could become important as an anti-aging therapy, in my opinion. We’ll just have to wait and see.

Meanwhile, keep bones strong via weight-bearing exercise. Resistance (strength) training is the most beneficial for bones, and ought to be the best for maintaining high levels of osteocalcin.

By the way, vitamin K2 is necessary to activate osteocalcin for bone remodeling, although as far as I can see, may not be necessary for improvements in brain and insulin function.

Dietary protein strengthens bones too.

PS: For related material, see my books, Muscle Up and Dumping Iron.

PPS: Check out my Supplements Buying Guide for Men.

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Low Testosterone Is Associated with Insulin Resistance

Testosterone (T), the hormone that gives men their male sex characteristics, declines with age. T is also declining over time, i.e. a men of any age have lower T levels than men the same age 20 or more years ago. Could one factor explain both types of decline? The fact that low testosterone is associated with insulin resistance argues for an answer in the affirmative.

Testosterone and aging

Testosterone declines with age. See chart below. The measurement of T used here is nmol/L (nanomoles per liter); 1 nmol/l equals 28.8 ng/dl.



However, much of aging is just a consequence of poor health habits. Becoming over-fat and more sedentary are linked to aging as well as poor health habits. So how much of the decline in T with age is due to aging itself, and can it be mitigated?

The authors of the above-linked article note the same question and state that “the finding, in some studies, that T levels did not fall significantly with age in exceptionally healthy men raised the question of the relative roles of chronic age-related illness vs. aging per se in producing the observed decreases.” [My emphasis.]

In fact, in one study (cited here) men aged 80 to 89 in the upper 2.5 percentile has T levels averaging 964!

Clearly, decline of T with age is not a foregone conclusion. Good health can keep T levels high, at least in some – and I would argue, most – cases.

Testosterone and insulin resistance

Insulin resistance is characteristic of type 2 diabetes, although diabetes is only the extreme result of insulin resistance, which perhaps 80% of the population has to some degree.

Low testosterone is common in type 2 diabetics, with some 47% having T levels that indicate hypogonadism. However, hypogonadism is defined by a number which, while it isn’t totally arbitrary, represents a binary division, whereas T levels are on a spectrum. In other words, insulin resistance impacts the T levels of all men, not just diabetics, and just because one isn’t deemed clinically hypogonadal doesn’t mean that one’s T levels are optimal, or all that they could be.

Insulin sensitivity (the converse of insulin resistance) is strongly and positively correlated with T levels. This shows that even in men who aren’t clinically diabetic, their level of insulin sensitivity has a strong effect on testosterone.

Insulin resistance increases with age, but why? Insulin resistance is more closely associated with abdominal adiposity (visceral fat) than with age. When visceral fat was controlled for, aging accounted for <2% of the variance in insulin resistance.

Obesity and aging are linked. T levels are also linked to obesity, specifically visceral fat.

That means you can avoid many of the effects of aging on testosterone and in general many other factors by avoiding insulin resistance and staying insulin sensitive.

Testosterone therapy also improves insulin sensitivity. The two are closely linked.

To maintain the best insulin sensitivity:


Aging doesn’t cause low testosterone.

Unhealthy living that results in abdominal fat and insulin resistance does.

Staying lean, muscular, and insulin sensitive will do more for a healthy testosterone level than anything short of injecting yourself with it.

PS: For the best exercise for getting lean and muscular – and insulin sensitive – pick up a copy of my book, Muscle Up.

PPS: Check out my Supplements Buying Guide for Men.

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Blood Donation Increases Insulin Sensitivity

Insulin sensitivity is crucial to both health and slowing aging. Decreased insulin sensitivity (or increased insulin resistance, same thing) is associated with vastly greater risks of heart attack, stroke, cancer, and hypertension. Insulin plays a central role in aging. Having better insulin sensitivity results in lower insulin levels, less disease, and slower aging.

Blood donation increases insulin sensitivity

High body iron stores increase the risk of diabetes. Since diabetes is merely the end result or the extreme on a spectrum of insulin resistance, iron can be suspected of causing insulin resistance. But does it.

In blood donation, the removal of blood leads to lower body iron stores, since iron must be removed from storage to replenish the red blood cells lost during donation. Hemoglobin, the oxygen-carrying molecule of red blood cells, requires iron as a necessary co-factor.

Regular blood donors have lower body iron stores than non-donors, on average. (“On average” because certain groups, especially fertile women, have relatively low body iron. Fertile women are also much less prone to disease than men the same age or older women.)

It follows that blood donors ought to have better insulin sensitivity. Turns out that they do.

A group of blood donors had both better insulin sensitivity and lower iron than non-donors. That led to over 50% lower insulin secretion in a test in which glucose was infused into a vein, which can be expected to profoundly affect aging and disease risks.

A problem in studies of blood donors, as I discussed in my book Dumping Iron, is a so-called healthy donor effect. Blood donors are more likely to be healthier than non-donors, since if they are unhealthy they can’t donate, and this could account for some of the better health seen in donors.

A number of ways exist to get around the healthy donor effect to see whether blood donation truly causes better health, or whether there’s a mere association between the two.

In this particular study, donors were carefully matched with non-donors for “age, body mass index, waist-to-hip ratio, and cardiovascular risk profile, including blood lipids, blood pressure, and smoking status.” This matching could eliminate much or all of the healthy donor effect, if the participants were alike in every way except the fact of being blood donors.

Blood donors also had lower ferritin levels, which measures body iron stores. The ferritin of donors averaged 101 μg/L, that of non-donors was 162.

Blood donation causes better insulin sensitivity

To prove that lower body iron via blood donation actually causes better insulin sensitivity, 10 healthy blood donors had their iron lowered via phlebotomy. Serum ferritin was cut almost in half, from 75 to 38.

Insulin sensitivity increased by about 40%.

Similar results were seen in carbohydrate-intolerant patients with non-alcoholic fatty liver disease (NAFLD). In addition, their liver enzymes declined to nearly normal, indicating improvement in fatty liver.


Metformin is the most commonly prescribed drug for diabetics; it’s been shown to extend lifespan in animals, and may very well do the same in humans.

Much experimentation and speculation has gone into trying to explain how metformin works.

It turns out, according to a recent study, that metformin induces an iron deficiency-like state. In effect, metformin causes an organism to “believe” it’s in a state of low iron, which upregulates certain cellular processes that are known to prolong lifespan.

The connection between metformin and iron provides further evidence of the close linkage between iron and aging.


Blood donation is associated with better insulin sensitivity.

Phlebotomy (removal of blood) results in better insulin sensitivity.

Metformin both extends lifespan and causes an iron deficiency-like state.

Giving blood regularly and thus keeping body iron stores in the low normal range may give you the same life-extension benefits as metformin. Maybe even better.

PS: For more on the benefits of lower body iron, pick up a copy of my book, Dumping Iron.

PPS: Check out my Supplements Buying Guide for Men.

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cold thermogenesis

Cold Thermogenesis

Cold thermogenesis, or the generation of heat through exposure to cold, has become popular recently, or as popular as something like this can become. What’s the reality and how much is hype behind cold thermogenesis?

How cold thermogenesis works

Cold thermogenesis is the production of body heat during and after the body has been exposed to cold. The body must produce heat when exposed to cold, since all physiological and biochemical systems are designed to work at an optimal temperature, around 37° C. or 98.6° F.

In extreme cases, it’s a matter of survival.

There are two ways the body uses to increase the metabolic rate and produce heat: one is through the muscles and shivering, the other is through the activation of brown fat.

Brown fat is a metabolically active form of adipose (fat) tissue. The majority of fat tissue in adults is white adipose tissue, which is relatively metabolically inactive. Until recently, it was thought that only infants and children carry substantial amounts of brown fat, but it’s been discovered that adults have it as well.(1) Cold exposure activates brown fat.

In people who have brown fat, or enough of it to be detectable, cold exposure causes an increase in the metabolic rate.

Exposure to an air temperature of 19 C. (66 F.) while wearing light clothing (t-shirt and underwear) caused an approximately 30% rise in energy expenditure – basal rate was 1446 calories a day, and this increased by 410 calories. The BAT (brown adipose negative) group rise was only about 40 calories.

If this increased energy expenditure were to be repeated often enough, large amounts of calories would be burned. But to burn an extra 400 calories a day, presumably you’d have to sit in a cold room in your underwear 24 hours a day.

Water has a high heat capacity, higher than air, meaning that in cold exposure, water will make the body colder in less time than air. Cold water exposure is therefore a more efficient way to cool the body; it’s also more efficient at killing people at extreme temperatures than air. (Allegedly, a pilot who ditched in the North Sea during WW2 had only a minute or two to get out of the water before he died.)

So, what happens to people in cold water exposure? Immersion of the entire body, with head out, in water of 20 C. (68 F.) causes a near doubling (93%) in the metabolic rate. If that were continued over 24 hours, that might mean 1500 more calories burned.(2)

Exposure to cold water at 14 C. (57 F.) ramped up the metabolic rate by 350%, or 4.5 fold. That’s the equivalent of an extra 6750 calories daily, or around 280 calories an hour.

Cold showers

Cold showers have the potential to treat depression, chronic fatigue, and possibly even cancer, through their effects on the immune system. Cold showers will not be as effective as complete immersion in cold water for raising the metabolic rate, but they offer a reasonably good alternative.

I take a cold shower daily. I recently (November) measured the temperature of the water in my shower, and it was 66 F. (19 C.) That temperature feels cold enough when you first step into it, but you get used to it quickly and it soon feels normal. The temperature of shower water varies a good deal, depending on your local conditions, and could be much colder or warmer. My January water temperature is around 55 F. (13 C.)

We saw above that a one-hour exposure to air of about the same temperature as the water in my shower caused an approximate 30% increase in metabolic rate. Since water is more efficient than air in this respect, we might guess that 5 minutes in a cold shower would have the same effect. While this is guesswork, judging by my subjective experience, it’s in the ballpark.

Other than coffee, there’s nothing like a cold shower to get you going in the morning. They take you from that soft cocoon of warmth and sleepiness to ready to take on the day. But will they help you burn fat?

If my metabolic rate increases 30%, and that lasts an hour (which may be generous), then I burn an extra 21 calories through cold showering. So no, that’s not going to help me burn fat.

If I were to take a shower at a colder temperature, 57 F. (14 C.), and stay in for an hour, and the increase in metabolic rate lasted two hours (again, probably generous), then I might burn an extra 560 calories. Now we’re getting somewhere – but unless you do this daily, it’s not likely to make a lot of difference in calories burned.

Cold vs exercise

People seem to be interested in the topic of cold thermogenesis as a way to increase calories burned without actually doing anything. In other words, increase your metabolic rate and you’ll burn more fat just sitting there. But there are a couple of problems with this notion.

One is that exercise burns a lot more calories than any reasonably credible increase in metabolism through cold exposure.

The amount of energy expenditure through exercise is often measured in terms of metabolic equivalents, or METs. A MET is the increase in energy expenditure as a ratio of basal metabolic rate. Sitting quietly has a MET of 1.0. Brisk walking and tennis both have a MET of 5,  jogging and cycling a MET of 10. Other high-intensity exercises have a yet greater effect, sprinting or jumping rope, for instance.

Even moderate exercise increases the metabolic rate quite a bit more than exposure to very cold water. If you wanted to burn more fat, you’d be better off going and playing tennis for an hour than you would taking a cold shower for the same length of time.

Furthermore, a game of tennis is bound to be more enjoyable.

The final objection to the notion of increasing metabolic rate to burn fat is the same as with exercise: it’s very easy to make up for what you have burned by eating more. Aerobic exercise has a poor record at fat loss, so poor in fact that most actual experts say it does next to nothing. (I discussed this extensively and cited relevant studies in my new book, Muscle Up.)

Increased metabolism has no advantage over exercise in this regard; it is not magic. If you don’t control your food intake, then nothing you do in the way of either exercise or increased metabolism will matter much for weight loss.

Like exercise, increasing the metabolic rate will have similar beneficial effects on health. But unfortunately, fat loss isn’t one of them.

Increasing brown adipose tissue (BAT)

As I discussed in my book, there is an exception to the rule that exercise doesn’t cause fat loss, and that is resistance training (strength training, weightlifting). The reason that this form of exercise works is because it builds muscle and reduces insulin resistance; muscle has a higher metabolic rate than fat tissue, and better insulin sensitivity allows for fat to be burned off more readily.

By increasing the amount of actively metabolic tissue (muscle), weightlifting causes more calories to be burned even at rest. Weightlifting has been shown to be much more effective for fat loss than aerobic exercise – albeit watching one’s food intake is still important.

Brown adipose tissue, as we saw above, burns more calories than white adipose tissue; BAT appears to be the main component of increased metabolic rate, short of shivering, which is a function of the muscles. Therefore if we increase the amount of BAT, this will, just like the addition of muscle, burn more calories around the clock. But can this be done?

There are some indications that it is possible to increase BAT. A group of people, aged 20 to 73, underwent cold exposure and were tested for the presence of BAT.(3) Among people in their 20s, more than half of them tested positive for BAT, but among people older than 60, that figure dropped to 10%. Furthermore, those who tested positive for BAT had a lower BMI, and less body and abdominal fat.

So there’s some indication not only that more BAT means less body fat, but that the incidence (and presumably, the amount) of BAT declines with age. If BAT declines with age, that means that certain measures may be able to combat the loss of BAT, just as certain measures can combat other aspects of aging.

Inactive or inefficient BAT is also seen in obesity.(4) So an increase in quality – likely meaning better mitochondrial function – may also mean less body fat.

Since cold exposure causes more BAT activity, it stands to reason that repeated cold exposure may increase the amount of BAT. Whether it actually does so is not known.

As for increasing BAT quality, anything that improves mitochondrial function should help. That includes exercise, and supplements like resveratrol and curcumin.  A diet low in carbohydrates should help too.

Certain food ingredients and other supplements also activate BAT(5), including capsaicin, cinnamon, black pepper, and green tea catechins.


Certain figures in the world of biohacking have generated a lot of hype about cold thermogenesis, probably because it’s new and different and people are desperately seeking solutions for fat loss. As we’ve seen, cold thermogenesis isn’t a panacea by any means. It’s generated at the cost of quite a bit of discomfort, and whether it will truly result in fat loss, and how BAT may be related to the obesity epidemic, are all but unknown.

My take on this is that cold exposure, such as a cold shower, has decided benefits, just as exercise does. But if not combined with a decent diet then one should not expect fat-loss miracles.

(Article updated 11/26/2017.)

PS: For more on exercise and fat loss, pick up a copy of my book, Muscle Up.

PPS: Check out my Supplements Buying Guide for Men.

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Why You Should Never Feed Your Child Commercial Infant Formula

Commercial infant formula is an abomination, a concoction of chemicals and industrial “food” that you should never feed your child. Here’s why.

After weaning

Over the Thanksgiving holiday, I came across a “food product” called Enfagrow that a relative was feeding her one-year-old boy. Enfagrow is meant to be given to toddlers age 1 to 3 after weaning, and is billed as “Toddler Next Step”.

Here are the ingredients:

The first 3 listed ingredients are non-fat milk, corn syrup solids, vegetable oil. Then following are some chemicals, a multivitamin and mineral supplement, natural flavor, and soy lecithin.

Non-fat milk (in this case, it’s also powdered) has all the healthy milk fat removed. Milk fat contains EPA, DHA (both omega-3 fatty acids) and conjugated linoleic acid, a potent anti-cancer molecule. Skim (non-fat) milk is used to fatten pigs. Think it might have the same effect on children and other people? I do.

Corn syrup solids are a concentrated, dried form of corn syrup, a form of sugar in other words. Sugar in any but small amounts is a health disaster.

Vegetable oils are better known as industrial seed oils, and these are also a health disaster.

Why in the world would you give this to an infant, or anyone you cared about.

You might as well feed them Coffeemate.

This product is made by Meade Johnson, a corporation whose 2016 revenues were $3.7 billion. Think they really care about your child’s health?

As an infant

Not satisfied that you have to wait until they’re one year old to feed them this chemical abomination? Instead of breastfeeding, you can give them chemical formula.

Here’s a popular formula, along with its ingredients:

First 4 ingredients: corn maltodextrin (a refined carbohydrate consisting of chains of glucose molecules), industrial seed oils, soy protein (which in my opinion no one should consume), and sucrose, i.e. table sugar.

This product has all the industrial foods in the first one with the addition of another, soy protein.

The Diseases of Civilization Starter Pack

What happens when babies consume soy? Exposure of infants to phyto-oestrogens from soy-based infant formula:

The daily exposure of infants to isoflavones in soy infant-formulas is 6–11 fold higher on a bodyweight basis than the dose that has hormonal effects in adults consuming soy foods. Circulating concentrations of isoflavones in the seven infants fed soy-based formula were 13 000–22 000 times higher than plasma oestradiol concentrations in early life, and may be sufficient to exert biological effects, whereas the contribution of isoflavones from breast-milk and cow-milk is negligible.

As Dr. Greiner remarked over on twitter, it’s like giving your child 5 birth control pills daily. A huge exposure to estrogenic compounds.

These two products together might be called the Diseases of Civilization Starter Pack. Lifelong exposure to so-called “food” like this will lead to obesity, diabetes, cancer, and heart disease. Can’t get ’em started on the road to diabesity too young.

Unfortunately, not only does Big Food not care a whit about your or your children’s health, but most people just accept these chemical concoctions as par for the course. Personally, I wouldn’t feed them to a dog.

Usually I write about men’s health and fitness in these pages, but this is an important issue. men have children, and presumably they (and the mothers of their children) want them to grow up to be healthy, lean, and with no endocrine problems. Be aware of these industrial abominations called infant formula.

PS: If you liked this post, pick up one of my books, like Dumping Iron.

PPS: Check out my Supplements Buying Guide for Men.

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What an Amish Mutation Can Tell Us About Long Life

A new study found that people with a relatively rare mutation live longer than those without it. The mutation was found among the Amish people in Indiana, and what this mutation does says a lot about what makes for longer life, and what we can do about it. Here’s what an Amish mutation can tell us about longer life.

The mutation

The mutation in question is for a gene called SERPINE1, which encodes for a protein called plasminogen activator inhibitor 1. A null mutation in SERPINE1 protects against biological aging in humans. (Thanks to commenter anonymous human for bringing this to my attention. Josh Mitteldorf wrote about what these results mean for a theory of programmed aging.) From the abstract:

Plasminogen activator inhibitor–1 (PAI-1) has been shown to be a key component of the senescence-related secretome and a direct mediator of cellular senescence. In murine models of accelerated aging, genetic deficiency and targeted inhibition of PAI-1 protect against aging-like pathology and prolong life span. However, the role of PAI-1 in human longevity remains unclear. … We studied 177 members of the Berne Amish community, which included 43 carriers of the null SERPINE1 mutation. Heterozygosity was associated with significantly longer leukocyte telomere length, lower fasting insulin levels, and lower prevalence of diabetes mellitus. In the extended Amish kindred, carriers of the null SERPINE1 allele had a longer life span. Our study indicates a causal effect of PAI-1 on human longevity, which may be mediated by alterations in metabolism. [emphasis added]

Those Amish who were heterozygous for this mutation lived about 10 years longer on average than others. See chart below:

Just eyeballing the chart, median survival of carriers was about 85, for others about 75. That’s a huge increase in lifespan, arguably much greater than almost any single factor we know in humans.

The carriers of the gene mutation produce less PAI-1, which results in a greater tendency for blood clots to break down. Those who are homozygous (-/-) for the mutation have an even greater tendency to break down blood clots, which results in a bleeding disorder. That’s the immediate consequence of less PAI-1.

However, the heterozygous (+/-) carriers had longer telomeres, which is a sign of slower aging. They also had less diabetes risk, a 0% diabetes rate compared to 7% in non-carriers, even though body mass index was the same. And they had better cardiovascular risk markers, including lower blood pressure and lower carotid artery thickness, a measure of atherosclerosis.

Clearly, PAI-1 does a lot to promote aging, and having less of it appears to result in longer life.

What does this mutation tell us about the conditions necessary for longer life, and can we do anything about it?


Blood coagulation is a necessary function that protects animals from excessive bleeding, which obviously can be fatal. When a cut or injury appears, whether internal or external, many different proteins are activated to form a blood clot; regulation of the coagulation cascade is complex, and the organism must balance all these factors to have an optimal coagulation system.

If the coagulation system becomes out of balance, either bleeding or hypercoagulability result, both of which are deleterious.

Aging promotes hypercoagulability, which generally arises from a decreasing ability to break down fibrin blood clots. This can result in thrombophilia, in which blood clots spontaneously form when not wanted and cause serious problems. The incidence of venous thromboembolism, or a blood clot in a vein, rises sharply with age. See chart below.

Several factors can promote hypercoagulability, among them bacterial lipopolysaccharides (LPS) and iron.

Iron causes irregular fibrin clots which resist breaking down.

Iron also promotes the growth of bacteria, and gram negative bacteria shed LPS, tiny amounts of which promote blood clotting.

So the first thing we can learn from the relation between less PAI-1 and longer life is that hypercoagulability can and should be avoided.

Aspirin may play a role in this, and in fact preventing blood clots is one way in which it prevents heart attacks – and also promotes bleeding.

Keeping iron in the low normal range and cultivating good gut integrity and oral hygiene to prevent incursion of gram negative bacteria can help prevent hypercoagulability in aging.

Insulin resistance

Why having less PAI-1 leads to less diabetes seems mysterious, but it does.

Type 2 diabetes is characterized by insulin resistance, which also rises with aging and obesity. Having low insulin resistance, or conversely, high insulin sensitivity, is one of the most important health risk factors.

Young, lean, fit people who eat few refined carbohydrates or sugar have the best insulin sensitivity.

Old, overweight, sedentary people who eat high carbohydrate and high sugar diets have poor insulin sensitivity.

The Amish mutation that resulted in less PAI-1 also shifted their metabolic type closer to that of the young, lean, etc. Adipose tissue is one of the main producers of PAI-1.

If you’re not so lucky as to have the mutation, you can still avoid sugar and refined carbohydrates, you can exercise, and you can stay lean. Same effect.

Cellular senescence

Increased gene expression for PAI-1 is increased in senescent cells.

Senescent cells as contributory to aging is an exciting field of research that has made a lot of advances in recent years. Ridding mice of senescent cells greatly improves their health, giving them higher exercise capacity and better cardiac function.

Currently, trials in humans are contemplated to try to eliminate senescent cells, and will probably in a few years result in senescent cell therapy, which would probably only need to be done periodically, say every few years.

The Amish mutation study shows the importance of cellular senescence in aging.

Heart disease

The Amish who had this mutation had better cardiovascular risk markers.

PAI-1 has a causal effect on coronary heart disease. It also increase fasting blood glucose.

The fact that less PAI-1 means less heart disease and longer life shows its importance.

It also seems to show that cholesterol isn’t a great risk factor for heart disease, if indeed it is at all.


The degree of life extension conferred by the SERPENTINE1 mutation was large, 10 years or so.

As we’ve seen above, the result confirms the importance of hypercoagulability, insulin resistance, and cellular senescence to aging.

It’s likely possible to get the same results through the lifestyle and other factors outlined in this article.

PS: For more on the importance of iron and aging, see my book, Dumping Iron.

PPS: Check out my Supplements Buying Guide for Men.

Fasting Insulin

A blood test for fasting insulin can be one of the most important that you get.

It’s important because it shows the degree of insulin resistance: the higher the number, the more insulin resistant. A very high number generally means type 2 diabetes. A number merely higher than normal can signify metabolic syndrome or pre-diabetes.

Hyperinsulinemia, or too much insulin in the blood, is one of the main causes of chronic disease in the modern world, including heart disease, cancer, kidney disease, and of course diabetes.

Being sedentary leads to insulin resistance, and exercise can prevent it.

Insulin resistance is strongly associated with obesity, but normal weight people, especially those who are skinny-fat, can have it too.

A diet high in sugar and refined carbohydrates, especially when combined with seed oils, leads to hyperinsulinemia and insulin resistance.

My fasting insulin test

Doctors don’t routinely test for fasting insulin; they normally do so only if they suspect diabetes.

I’ve had a few tests of fasting blood glucose that were high, in the range of 100 to 110. That’s an odd result, because I eat a low-carbohydrate diet and lift weights, and have a body fat percentage that I don’t know exactly but is likely <15%.

It’s probably due to the so-called dawn phenomenon, or physiological insulin resistance, which is normal. When on a low-carbohydrate diet, the liver can become insulin resistant in order to make glucose for the rest of the body. To be honest, the causes of the dawn phenomenon are not fully elucidated, and experts give varying explanations. But the fact is that many people who eat low-carb report it.

Another reason for a high fasting glucose can be stress and cortisol; if you go for a blood draw on a morning when you’re rushing off to work, for instance, that could elevate your glucose.

Not being clear on whether I should be concerned about my high fasting glucose, I decided to get a fasting insulin test from Life Extension.

Result: 2.9 µIU/ml. Normal range is 2.6 to 24.9. (On this scale, 1 µIU/ml = 6.9 pmol/L.)  Ideal is <3. The odds ratio for prediabetes rises sharply with increased fasting insulin.

My result was close to ideal. I think I’m going to live another few years.

Should I remain concerned about my fasting glucose test? Probably not; my non-fasting glucose is actually lower than my fasting glucose, which would seem to indicate, together with my insulin test, that I have no risk of diabetes. It would indeed be strange if I did have increased risk, for the reasons mentioned above: low-carb diet, weight lifting, low body fat, plenty of muscle too.

If you do have a high fasting insulin, then you need to get to work. Below are relative risks of hypertension, high triglycerides, and diabetes based on fasting insulin levels. (Source.)

Image result for fasting insulin

To lower a fasting insulin value, two interventions are important:

  1. Avoid sugar and refined carbohydrates
  2. Exercise.


You can order a fasting insulin test through Life Extension; blood is drawn at no extra charge at LabCorp.

PS: Read my book, Stop the Clock, for why insulin sensitivity is important.

PPS: Check out my Supplements Buying Guide for Men.

Exercise Capacity, the Most Important Health Risk Factor

Exercise capacity is closely related to both aging and to health. Exercise capacity declines with age, and people with low exercise capacity have higher health risks. In fact, exercise capacity is the most important health risk factor. Fortunately there’s some good news that means that older people can robustly increase their exercise capacity.

Exercise capacity and health

Exercise capacity is exactly what it sounds like, the amount of exercise someone is capable of doing. It’s closely related to VO2max, the maximum oxygen uptake while doing exercise.

A study published in the New England Journal of Medicine of men who were referred for exercise testing divided the men according to quintiles (fifths) of exercise capacity, and then followed them over time.

“Exercise capacity is a more powerful predictor of mortality among men than other established risk factors for cardiovascular disease.” See chart below.


In normal men without cardiovascular disease, those with the lowest exercise capacity were 4.5 times as likely to die within the follow-up time than those with the highest exercise capacity.

If exercise were a pill, doctors would prescribe it to everyone. There’s no drug or supplement as powerful as exercise in promoting health.

Exercise capacity declines with age

If aging is an increasing tendency toward breakdown of biological systems and increasing tendency to ill health – which it is – then it stands to reason that exercise capacity declines with age – which it does. We could expect that declining exercise capacity and the tendency to ill health would be closely related, and they are.

A study of several hundred people in the Baltimore Longitudinal Study of Aging found not only a strong decline in exercise capacity with age, but that decline also accelerates with age. This held true even when adjusted for lean body mass, which also declines with age. See chart below.

This decline in exercise capacity is a disaster for health. I know a man in his late seventies who gets winded from walking, and that may be typical for the average man that age who doesn’t exercise and is overweight.

But is it inevitable?

Older people robustly respond to exercise

It’s been thought that older people would not be able to respond to exercise training with as great an increase in exercise capacity as younger people. Turns out, that’s not true, at least in the case of high-intensity interval training (HIIT).

A study done in Norway took 94 people, aged 20 to 83, and put them through a high-intensity interval training program. Against their hypothesis, age was not related to the amount of improvement in fitness.

Initial training status, which would be better formulated as initial fitness level, or initial exercise capacity, was related to improvement. In other words, those with the lowest level of fitness improved the most. Not surprising – newbie gains.

In this study, the older groups even showed a tendency towards higher maximum heart rates, which decline with age.

Therefore, the declining level of fitness seen in aging may be at least partly due to decreased physical activity, not an inevitable consequence of aging. To be sure, an older athlete can never compete at the highest levels with a younger one, so aging does intrinsically affect our biology in a way that makes for lower maximum exercise capacity.

Exercise capacity, the most powerful determinant of health and longevity?

Men who have low exercise capacity have nearly a five-fold higher risk of death per period of time than men with a high exercise capacity. (See first chart above.)

I can’t think of any other factor among nominally healthy people that shows such a large difference between low and high levels. Not cholesterol, LDL, or HDL. Not blood pressure. To be sure, these are related to exercise.

In fact, in men aged 75, exercise capacity was the most powerful predictor of survival until age 90. (Source. For women, it was low white blood cell count.) See chart below.

The most interesting finding, especially among men, was the strong association between survival and results from the exercise test, including high exercise capacity as measured by MET, high HRR after 4 minutes recovery, and high systolic BP rise during exercise. The prognostic importance of these factors greatly exceeded that of common prevalent diseases such as diabetes, hypertension, asthma, and angina pectoris/previous MI as well as that of conventional risk factors such as smoking, high BP, high level of TC, low level of HDL-c and obesity. [Emphasis added]


Exercise capacity is the most powerful health risk marker for men.

To get and remain healthy and to live a long life, exercise is a must. The higher your exercise capacity, the greater the odds of long life.

Exercise also gives you the best odds of feeling well, both mentally and physically.

Exercise should be a lifelong pursuit.

PS: For a great exercise program, including strength training and HIIT, see my book, Muscle Up.

PPS: Check out my Supplements Buying Guide for Men.

Healthy Drinks

Lots of attention has been given to what food is healthy and what isn’t, but less has been given to which drinks are healthy. The list of healthy drinks is surprisingly limited.

Don’t drink calories

If you want to stay lean and healthy, a cardinal rule is don’t drink your calories.

Drinking caloric beverages with a meal, whether the beverage is milk, cola, or orange juice, leads to the consumption of more calories, but with no change in satiety. If you drink calories, it doesn’t seem to subsequently change the amount of food calories you consume.

There’s something about liquid calories that doesn’t register with the normal appetite control system, so if you drink calories, that could put you on the road to weight gain, or stall weight loss.

It’s not just calories either. Most commercial beverages are loaded with sugar. Since they don’t have any fiber, if you consume them alone, they’re going to spike your blood sugar and insulin, always a bad thing.

The rule not to drink calories (or sugar) immediately knocks most commercial drink products off the list.

Healthy drinks

Warning: this is going to be a short list.


If you’re thirsty, drink water.

Thirst is telling you that you need water, and nothing else. It’s not telling you that you need a soda or orange juice or a Starbucks coffee milkshake.

Water has zero calories. When drunk with a meal, it may actually improve satiety by making you feel fuller. It also seems to be the case that we can mistake thirst for hunger, thus quenching thirst may make us less hungry.

There are a number of commercial drinks now that are just sparkling water (plain) or with a bit of flavoring added. These are fine as they have no added sugar. For example, La Croix:

LaCroix Sparkling Water, Lime Flavor, 12oz Can, 24/Carton ...

San Pellegrino or other sparkling waters make for a good summer or post-workout thirst quencher.

San Pellegrino Sparkling Mineral Water Reviews ...

If you’re thirsty, do not drink Gatorade or similar drinks that are loaded with sugar.

Coffee and tea

If you need an energy boost, drink coffee or tea. Small amounts of cream or half-and-half added are acceptable. Sugar is not.

Coffee and tea are among the most consumed drinks in the world, which is a good thing, because they’re healthy. Consumption of coffee and tea are both associated with lower death rates. They contain phytochemicals that stimulate hormesis, much more than even most fruits and vegetables. When drunk with a meal, they also chelate iron, preventing its absorption. In fact, people in underdeveloped countries consume so much tea and have low dietary iron sources that researchers worry that tea could contribute to iron deficiency anemia. However, that’s not much of a worry for those of us in developed countries; iron overload is more of a concern.

The caffeine in coffee and tea can contribute to anxiety, and in extreme cases, to caffeine psychosis. I’ve known people, night shift workers, who drank coffee continually, maybe a dozen or more cups in 8 hours, and that’s certainly something most people should avoid. However, contrary to folk knowledge, the consumption of caffeine is not linked to risk of atrial fibrillation.

Tea contains other psychoactive compounds besides caffeine, notably theophylline, theobromine, and theanine, and these may have lower effects on anxiety than caffeine. Tea also has a lower caffeine content than coffee, and for these reasons, as well as the seemingly more favorable health profile of tea, I’ve cut way back on coffee consumption and increased my tea consumption lately.

Herbal teas can be toxic. Rule of thumb: if an herbal tea doesn’t use a plant that humans have long experience with, stay away.

If you get coffee from a coffee shop, don’t get those coffees loaded with sugar, syrup, or soy. They’re just milkshakes in disguise.

Red wine

If you drink alcohol, red wine is arguably the healthiest alcoholic beverage. “Arguably”, because data is mixed and much of the data is epidemiological, meaning it can’t show causality.

Also, one to two glasses and not more confers most of the benefit.

Red wine contains polyphenols, much like coffee and tea, that appear to provide much of the health benefit behind the Mediterranean diet.

If you like an occasional cocktail, choose plain highballs or other non-sugared drinks. Beer isn’t a great choice, as beer belly is real, although an occasional beer won’t hurt.

What not to drink

You shouldn’t drink virtually everything else in the way of commercial beverages.

Fruit juice: 12 fluid ounces of orange juice contains about 31 grams of sugar, which isn’t much less than in soda pop. Fruit isn’t even necessarily healthy, and in any case, you should chew your own food.

Commercial drinks that are mostly carbonated water with a bit of fruit flavoring and minimal sugar probably won’t hurt you.

Diet soft drinks may have some downsides.

Every overweight/obese person around seems to constantly have a sugar-sweetened drink of some kind in their hands at all times.

Just because that sugar-loaded drink is made from fruit, or came from Starbucks, does not make it healthy. They lead to weight gain and inability to lose weight, not to mention insulin resistance and heart disease. Not to mention that cancer cells have a voracious appetite for sugar.

I’m probably forgetting a lot of other commercial drinks, since I’m just not attuned to what the masses are doing. If you want to stay lean, muscular, and healthy, you need to avoid what they’re doing.


If you’re thirsty, drink water.

If you need an energy boost, drink coffee or tea.

If you need to relax, drink a glass of red wine. (Moderation is key.)

If you want to stay lean, muscular, and healthy, and live a long time, don’t drink anything else.

PS: Staying lean, muscular, and healthy is the topic of my book, Muscle Up.

PPS: Check out my Supplements Buying Guide for Men.

Americans Are Now Fatter Than Ever

The obesity epidemic shows no signs of slowing, and Americans are now fatter than ever. When looked at in terms of body fat rather than body mass index (BMI), the numbers become astronomical. No use sugarcoating this.

Obesity rate hits a new high

America’s obesity rate has hit a new high, with nearly 40% of adults obese.

Obesity Rises In America | Odyssey

Obesity, it’s important to note, is just a stronger form of being overweight. When you add the figure for being overweight, some 71% of adult Americans are overweight/obese. As the above figure shows, the numbers are projected to get worse.

Body mass index (BMI), however, is not the best measure of the health consequences of being overweight. BMI can both overestimate and underestimate obesity. Overestimation is less common, mostly being confined to power and strength athletes, whose muscle mass makes them appear too heavy for their height, when in fact they’re in better metabolic health. There aren’t too many of those as a percentage of the population.

Underestimation is more common. Many people with a “normal” BMI in reality carry too much body fat. These have been designated as “normal weight obese“, otherwise known as skinny-fat. When we look at excess body fat alone, the figures for overweight/obesity soar.


Overfat is the condition of having more body fat than is good for health.

When the figures for people with too high body fat but normal weight are added to the figures for overweight/obesity, 91% of adult Americans are overfat. The figure for children is 69%. Chart below.


The percentage of body fat that can cause health problems, especially cardiometabolic risk, is surprisingly low.

Lohman’s criteria of suggested cutoffs >17.6% for males and >31.6% for females is widely accepted in body composition research. However, measurable health impairments associated with ≥2 cardiometabolic abnormalities were found at DXA-derived body fat levels >15.3% in men and >29.8% in women.

A man with more than 15.3% body fat, and a woman with more than 29.8%, are at higher health risk and are overfat.

Below are some examples of what different body fat percentages look like.

Quick cutting question ( cheatday, cardio, food) - Forums

Body fat, health, and aging

It should be clear that the health consequences of excess body fat lie on a continuum, which is why body fat percentages that are not even terribly high are associated with health risks.

So, one of the requirements for being healthy and for living as long as possible are to stay lean.

You don’t see many fat centenarians, and that’s no coincidence.

Why are Americans getting fatter?

Americans are getting fatter for two reasons.

  1. The advice they get is terrible.
  2. Many want to make no sacrifices or exert much effort.

The advice to eat low-fat, to graze (eat all the time), to consume “healthy whole grains”, to count calories, or to exercise to “burn” calories is all bad advice that has been repeatedly shown not to work.

The best diet for weight loss is one that the mainstream condemns. As for exercise, the notion of burning excess calories is next to nonsensical.

As for sacrifices, even when people do get good advice – not often, admittedly – many won’t take it. They like their carbs and junk food and consider it an imposition to give them up. Complacency rules. While it may be true that nobody wants to be fat, how much they dislike it seems debatable.

PS: For more on how staying lean and muscular is important to long life, see my book, Muscle Up.

PPS: Check out my Supplements Buying Guide for Men.

Cleansing and Detox Don’t Work and Are Pseudo-Health Practices

“Cleansing” is the practice of using a special diet for several days or even weeks with the end of cleansing the body of toxins, a “detox”. Unfortunately, the evidence for any benefit is limited or non-existent. Cleansing and detox don’t work and are pseudo-health practices.

The idea behind cleansing

If we need to be “cleansed”, that implies that we’re dirty or fouled in some way. In most cases, it’s claimed that the practice of “cleansing” rids our bodies of “toxins”.

However, what these toxins are never seems to be quite explained. Some some sort of vague bad stuff that our bodies can’t rid themselves of on their own.

The body does have mechanisms to rid itself of toxins. The most important organs for that process are the liver, kidneys, and intestines. On the cellular/molecular level, various classes of enzymes such as cytochrome P450 and phase II enzymes perform tasks like neutralizing drugs or toxins and preparing them for excretion.

In a normally healthy human, these mechanisms are at work constantly. Some interventions notably increase the activity of Nrf2, the regulator of phase II enzymes, and these include exercise, fasting, and certain phytochemicals such as resveratrol and curcumin.

Another important way that cells cleanse themselves is through the process of autophagy, in which molecules and cellular organelles that have become degraded through passage of time are broken down and recycled. In this case, however, we can’t really call these things toxins, since they’re normal, but worn-out, cellular constituents.

The practice of cleansing

The practice of cleansing has many variations, such as vegan cleansing and juice fasting, and programs vary greatly depending on who’s advocating them.

Absence of animal foods is prominent in most of them, as well as refraining from alcohol and caffeine, with addition of lots of high-fiber fruits and vegetables, so we may be able to generalize cleansing diets as low-calorie, high fiber, and vegan. Juicing is also prominent.

For example, Dr. Mehmet Oz claims that his cleanse “optimizes” the  body’s detoxification system, although he presents no evidence that it does. Among the foods he recommends are quinoa with prunes for breakfast, and a “revitalizing fruit smoothie” for lunch. Oprah tried a 21-day vegan cleanse, and didn’t like it much.

Other cleansing systems promote foods like “green smoothies” and “beet burgers”.

Cleansing promotes an almost magical or mystical belief in the power of fruits and vegetables. While fruits and vegetables may have benefits – though I’ve become more agnostic on that front – the idea that consuming super-high amounts of them while refraining from animal products confers extra benefits seems without foundation. If 5 servings of them a day is good (maybe), it doesn’t follow that 20 is better.

Smoothies are an artificial form of food, since food in its natural form must be chewed or chewable to be healthy. If fruits and vegetables are healthy, turning them into smoothies could very well make them unhealthy in general, or diminish their health benefits. It’s rather odd that with all the emphasis on greens and naturalness that you need a blender to cleanse.

The thinking behind cleansing (if there is any) harks back to the idea that we can return to the Garden of Eden, where we lived in peace and harmony and in good health, committed no violence, and all creatures were happy.

Puritanism is also strong here. One aspect of cleansing is a focus on bowel movements, hence all the high-fiber foods. Supposedly, this cleans our colons. In reality, some who practice cleansing report day-long watery diarrhea from all that quinoa and other stuff. (Personal correspondence.) Refraining from alcohol and caffeine also reflect puritanism, although of course doing that may confer benefits.

The good, the bad, and the ugly of cleansing and detox

Could cleansing and detox have a good side? Sure, and as usual, it all depends on context.

If someone were eating large amounts of processed, junk food, and refrained from that for awhile and ate more fruits and vegetables, that might be beneficial. Likewise, a cleanse functions as a low-calorie diet, so it might have the same advantages as a crash diet for an obese or diabetic person. (I’m struggling to think of other benefits.)

But junk food typically means sugar, refined carbohydrates, and vegetable (seed) oils. Animal products such as meat, eggs, and cheese are not junk, yet cleansing emphasizes not eating them.

However, there are much better ways of accomplishing these goals than a cleanse, which in any case is supposed to “detox”, a phantom goal.

The downsides of cleansing are many.

One is muscle loss. If you eat a low-calorie, low-protein vegan diet for any length of time, and lose weight, much of that weigh loss will be muscle, which should be avoided at all costs. A rule of thumb in weight-loss diets is that from 1/4 to 1/2 of weight lost will be muscle, unless you take in extra protein and lift weights.

Another downside is that people commonly report feeling awful on a cleanse, with fatigue, headaches, and diarrhea being prominent.

Cleansing and detox are pseudo-health practices.

True cleansing

As noted above, the process of autophagy breaks down cellular junk for recycling. As it happens, we have the means at our disposal to increase autophagy, which declines in aging. That means is via fasting.

Intermittent fasting strongly increases the process of autophagy; when the body senses that no nutrients are available, it breaks down cellular components to get them. When you eat again, the body rebuilds them anew. Cleansing may actually diminish autophagy, especially if you’re drinking smoothies, which if made from fruit have a high sugar content and raise insulin levels, cutting off autophagy.

Ketogenic diets may have nearly the same effect as fasting.

Exercise increases the activity of Nrf2, which leads to more of the important, detoxifying antioxidant enzymes such as superoxide dismutase and catalase. Exercise is arguably the most important thing you can do to make your body stress-resistant and toxin proof.


Cleansing and detox are pseudo-health practices that have little to no scientific backing. In some cases, they may do the opposite of what’s intended.

PS: For practices that will genuinely improve your health, see my book, Stop the Clock.

PPS: Check out my Supplements Buying Guide for Men.

Iron Supplements Increase Infection Risk

It’s been known for some time that iron supplements increase infection risk, because people who take them have more infections. A recent report clarifies some mechanisms.

Evidence for increased infections with iron

Many people in the tropics, especially children, are iron-deficient, given both the relative lack of dietary meat and high rates of intestinal parasites and malaria, so naturally doctors would like to fix that. Unfortunately, the most direct way, giving iron supplements, often backfires.

For example, giving iron to nomads in Somalia greatly increased the number of infections, compared to those who took a placebo.

Seven episodes of infection occurred in the placebo group and 36 in the group treated with iron; these 36 episodes included activation of pre-existing malaria, brucellosis, and tuberculosis. This difference suggested that host defence against these infections was better during iron deficiency than during iron repletion. Iron deficiency among Somali nomads may be part of an ecological compromise, permitting optimum co-survival of host and infecting agent.

Giving iron to children increases their risk of diarrhea and malaria, which in some cases requires hospitalization and can kill the patients. Many other reports (e.g.) and reviews describe similar findings.

Bacteria thrive with iron supplements

This next study is quite neat, since it’s simple and straightforward.

A group of adult male volunteers in the Gambia gave a blood sample. They then took one dose of ferrous sulfate, an iron supplement. at 400 mg, which is a typical or even low dose of iron. They then gave another blood sample. Both samples were centrifuged, and the serum was used to grow bacteria. The researchers discovered that oral iron acutely elevates bacterial growth in human serum.

Escherichia coli, Yersinia enterocolitica and Salmonella enterica serovar Typhimurium (all gram-negative bacteria) and Staphylococcus epidermidis (gram-positive) showed markedly elevated growth in serum collected after iron supplementation. Growth rates were very strongly correlated with transferrin saturation (p < 0.0001 in all cases). Growth of Staphylococcus aureus, which preferentially scavenges heme iron, was unaffected. These data suggest that even modest oral supplements with highly soluble (non-physiological) iron, as typically used in low-income settings, could promote bacteremia by accelerating early phase bacterial growth prior to the induction of immune defenses.

Bacteremia means a blood infection with bacteria, and is a serious, life-threatening condition. Also known as sepsis or septicemia, it’s ranked number 10 in the list of leading killers of people over 65 years old in the U.S. 

Below are growth curves for bacteria in serum before iron supplementation (blue lines) and after (red lines).

Figure 2

The y-axis on these charts is a log scale, x-axis is time, so the charts indicate doubling times and final concentration of bacteria. The bacteria grew far faster in serum from individuals after iron supplementation.

Bacteria and other microorganisms require iron

Why should bacteria grow so much faster with excess iron?

The answer is that bacteria, like virtually all living things, require iron for growth. However, in humans and other animals, iron is tightly controlled and sequestered, and one of the main reaons for this is to stop bacteria from acquiring iron.

Control of iron is an important part of the innate immune system.

The frontline of host-pathogen coevolution

Pathogens have to subvert a host’s innate defenses to avoid being killed. Barber and Elde now show that this principle extends to nutrient-transporting proteins, such as transferrin, which binds iron… Without iron, invading pathogens cannot replicate, but iron is sequestered in transferrin, which stops pathogens using it. So pathogens have evolved a succession of transporters that can hijack transferrin’s iron. Over time, the primate transferrin binding surface has coevolved to wrestle iron back from the grip of pathogens.

Transferrin is the protein molecule used to transport iron in the blood stream, and it’s been suggested that infusions of transferrin could be used in the treatment of septicemia.

Meat is a better source of iron

If someone were iron-deficient, a better way to get iron is eating meat. The iron in meat is heme iron, as opposed to the non-heme (unbound) iron in iron tablets. Heme iron is handled more safely by the body, and doesn’t result in spikes of iron in the bloodstream. In addition, heme iron doesn’t cause excess free iron in the gut, so bacteria can’t get it and use it for growth.

Iron supplements increase infection risk

Iron supplements increase the risk of infection.

In the U.S., all flour, corn meal, and rice must be iron-fortified by law. Is this increasing the rate of infections? How many people with gut dysbiosis and other problems such as irritable bowel syndrome owe their problems to iron fortification or supplementation? How many people with septicemia, the 10th leading cause of death among the elderly, got that way due to iron?

No one knows.

PS: For more on the effects of excess iron, see my book, Dumping Iron.

PPS: Check out my Supplements Buying Guide for Men.

How Much Exercise Is Too Much?

Exercise is known to be healthful, one of the healthiest things you can do. It’s said that if exercise were a pill, doctors would prescribe it to everyone, and high cardiorespiratory fitness is one of the best indicators for health and long life. Is there such a thing as too much exercise, and if so, how much exercise is too much? (Thanks to Josh Mitteldorf for pointing out the following papers.)

The J-curve for exercise

Exercise promotes hormesis, which is the beneficial effect on an organism of low doses of a toxin or stress. Exercise is a stress and indeed must be so to improve health. But too much stress is as bad as too little.

A comprehensive review, Exercising for Health and Longevity vs Peak Performance: Different Regimens for Different Goals, looks at the evidence that too much exercise is bad for health. For example, the following chart shows the incidence of atrial fibrillation (a cardiac arrhythmia) by levels of exercise volume and intensity. Important to note here, like so many others, the authors of this review don’t distinguish between intensity, which is the density of effort, and volume. Incredibly, the original paper to which they refer doesn’t appear to make that clear either.

Large image of Figure 1.

Those who exercised at high intensity and volume had a higher incidence of atrial fibrillation. The J-curve can be seen in the graph.

Marathon runners had greater volume of arterial plaque.

Large image of Figure 2.

Lifelong endurance athletes also have high rates (50%) of cardiac fibrosis.

What is the upper limit of exercise for good health?

On the basis of multiple studies, it might be prudent to limit chronic vigorous exercise to no more than about 60 min/d. This recommendation is reinforced by a trial of 60 men with stable CHD who were randomized to vigorous exercise sessions lasting either 30 or 60 minutes. The 30-minute exercise bouts enhanced arterial elasticity and generated minimal oxidant stress. In contrast, the 60-minute sessions amplified oxidant stress and transiently stiffened blood vessels, especially among men older than 50 years.

A weekly cumulative dose of vigorous exercise of not more than about 5 hours has been identified in several studies to be the safe upper range for long-term CV health and life expectancy. It may also be beneficial to take 1 or 2 days a week off from vigorous exercise and to refrain from high-intensity exercise on a daily basis. [my emphases]

So, what can we conclude from this review?

Endurance exercise of long duration causes these problems. All of the athletes in these studies were distance runners, cyclists, endurance skaters, cross-country skiers, and the like. None of them were sprinters or weightlifters.

High-intensity exercise is not a problem; high-intensity combined with long duration and high frequency is a problem.

Longevity of elite athletes

Another study reviewed the longevity of elite athletes. They (tens of thousands of athletes studied) had about a 27% lower risk of death from heart disease, and a 40% lower risk of cancer death.

The evidence available indicates that top-level athletes live longer than the general population and have a lower risk of 2 major causes of mortality, namely, CVD and cancer.

The full paper (behind a paywall but obtained through the wonders of the internet) states:

Although more research is needed using more homogeneous cohorts and a more proportional representation of both sexes, the evidence available indicates that elite athletes (mostly men) live longer than the general population, which suggests that the beneficial health effects of exercise, particularly in decreasing CVD and cancer risk, are not necessarily confined to moderate doses. Future studies might elucidate whether the present high demands of professional sports participation also translate into an actual longevity and health benefit. [my emphasis]

Unfortunately, the evidence for such a statement is sparse. The athletes studied included players of baseball, football (American), soccer, cyclists, track and field, and other Olympic events.

Clearly, not all of those athletes are endurance athletes, and may not be placing themselves under the kind of stress associated with hours of endurance running.

Another problem is self-selection. People become athletes in part because they’re good at it, and they’re in good physical shape, i.e. they’re healthy. Unless we can randomize people to becoming an elite athlete or not, then we can’t know how much of the longevity effect is genetic or from some other factor.


Too much endurance exercise can be unhealthy.

Very likely other kinds of exercise could be unhealthy too, if carried to an extreme. The volume of exercise that goes into professional bodybuilding, for example, could make it unhealthy, even absent the effects of steroids.

The amount of endurance exercise that makes for worse health is within the range of what many recreational runners do. (I know, because I used to do that much.)

High-intensity weightlifting, and high-intensity interval training, both of which are characterized by a relatively low volume of exercise, would appear to be safer for the heart, although more studies on these are needed.

PS: For more on how to live longer, see my book Stop the Clock.

PPS: Check out my Supplements Buying Guide for Men.

Is Fruit Healthy?

The idea that fruit is a health-giving food, or even that eating fruit is actually necessary for good health, is firmly entrenched in current dietary dogma. We’re told that we must eat at least 5 servings of fruits and vegetables daily for good health, with some recommendations going as high as 10 servings. But is fruit healthy, and do we really need to eat it for good health? Several considerations could lead us to an answer in the negative.

What our ancestors ate

Any consideration of whether a particular food or certain quantities of that food are beneficial for health necessarily depends on whether humans evolved to eat it. While some primates, to whom humans are related, eat lots of fruit, humans have evolved independently for a couple of million years or so, depending on how “human” is defined.

Hunter-gatherers are those groups of people that live without agriculture, and researchers have studied them and their diets extensively.

Since the origins of agriculture around 10,000 years ago, agriculturalists have pushed hunter-gatherer groups into more marginal areas, so how close the contemporary hunter-gatherer diet and lifestyle is to that of our paleolithic ancestors is an open question.

With that caveat in mind, contemporary hunter-gatherers consume a diet in which, on average, meat provides 65% of calories, the rest coming from plant foods. Our paleolithic ancestors may have consumed even greater amounts of meat, since they didn’t live on marginal land, the human population of the world was small, and many more large, wild animals roamed.

Did they eat fruit, and are humans adapted to eating it? Modern fruit consumption is based on agriculture and preservation, such as canning or refrigeration, and those certainly didn’t exist in the paleolithic era, so it’s a good assumption that if they did eat fruit, they would not have eaten nearly as high a quantity of it as modern people.

Paleolithic fruit eating could have taken the form of gorging on it when it was abundant and meat was scarce, in which case, fruit wouldn’t have been available year-round as it is for us moderns.

I’ve lived in the tropics myself, and virtually the only fruit I saw people there eat was mangoes. Mangoes ripen over the space of a few weeks and if not eaten then, fall to the ground and rot, so for a few weeks time, everyone eats mangoes like they’re going out of style – which they are, in a sense.

Optimal foraging theory

Optimal foraging theory applies economics to an animal’s acquisition of food. Like any other economic good, time and energy must be used to acquire food, and an animal attempts to spend the least time and energy for the most reward, or the greatest return on investment.

It seems that in most cases, optimal foraging theory points to meat as the preferred food of humans, since it is high in calories and protein. Fruit is not. A single large animal could feed a group of humans for days, while a lot of fruit would have to be gathered to feed the same number of people, arguably entailing a lot more work. Even then, fruit wouldn’t provide enough necessary protein, assuming that enough fruit could be gathered, which seems unlikely except perhaps sporadically. Golden Delicious apples didn’t grow in groves back then.

So, both theory and evidence point towards the consumption of large amounts of meat during the Paleolithic era. Nevertheless, humans probably ate fruit when necessary, when they were hungry, no meat was to be had, and fruit was available.

But what was that fruit like?

Wild vs domestic fruit

These are wild bananas:

Wild bananas around Chiang Mai | Dokmai Dogma

They’re much smaller and contain less edible material than modern bananas, which have been bred to have high sugar content.

One modern banana provides about 105 calories, of which almost all comes from sugars. It provides only 1 gram of protein. And, since bananas are grown, shipped, and stored using industrial technology, we can eat as many bananas as we like.

If sugar is bad for us, it doesn’t seem likely that just because it’s in a banana, it’s good.

The same considerations apply to other fruits: modern fruit is larger and contains more sugar because it’s been bred to be so, and it’s grown using modern methods resulting in abundant output, and then transported from the tropics or other areas to the point of purchase. In paleolithic times, none of that applied.

Modern era

What about more recent eras, such as the 18th or 19th centuries? Obesity and other diseases of civilization were uncommon then, and if people ate much fruit, then perhaps we could say that fruit was healthy, or at least benign.

In the 18th and 19th centuries, Americans did not eat very much in the way of fruits and vegetables. Meat was abundant, and even the poor ate plenty of it. Fruits and vegetables had a short growing season and were ripe for only a short period of time, and in the absence of refrigeration and transport, spoiled, as Nina Teicholz writes:

Even in the warmer months, fruit and salad were avoided, for fear of cholera. (Only with the Civil War did the canning industry flourish, and then only for a handful of vegetables, the most common of which were sweet corn, tomatoes, and peas.)

So it would be “incorrect to describe Americans as great eaters of either [fruits or vegetables],” wrote the historians Waverly Root and Rich­ard de Rochemont. Although a vegetarian movement did establish itself in the United States by 1870, the general mistrust of these fresh foods, which spoiled so easily and could carry disease, did not dissipate until after World War I, with the advent of the home refrigerator. By these accounts, for the first 250 years of American history, the entire nation would have earned a failing grade according to our modern mainstream nutritional advice.

What about apples – fruit, obviously – didn’t Americans eat them? Johnny Appleseed is famous for spreading apple trees around the country. But it turns out that much of the apple crop was turned into apple cider. Not only did cider provide alcohol, but it’s a way to preserve and concentrate apples in the absence of refrigeration and transport.


Modern fruit is typically loaded with sugar, although there are some exceptions. As noted above, bananas are sweet, with about 93% of calories as carbohydrates, most of that sugar. Apples are similar in composition, as are pears.

Even if it is argued that fruit contains protective or beneficial elements, which may be true, all that sugar does little good other than as an energy source, and energy sources are not in short supply these days. Fruit is a poor source of protein as well.

Berries are somewhat of an exception, with raspberries for instance containing about 33% sugar as calories. Avocados are low in sugar as well, although they don’t usually spring to mind when most people think of fruit.

Modern fruits are big bags of sugar, having been bred to be that way. If we avoid sugar in other forms, it seems odd that sugar would be beneficial just because it’s in fruit. Sugar is a huge net negative for fruit in my opinion.

Phytochemicals and hormesis

Fruits (and vegetables) are thought to be healthy due to the phytochemicals, largely polyphenols, that they contain. Phytochemicals in turn may be beneficial because they stimulate hormesis, the process in which low doses of a toxin or other stress produce beneficial changes in our bodies.

However, coffee, tea, red wine, and chocolate all generally provide far more polyphenols than fruit. With the exception of chocolate, they have the added benefit of being entirely sugar-free, and even chocolate can be consumed without sugar or in low-sugar forms such as dark chocolate. So, if you want to consume polyphenols, and you consume coffee, etc., then fruit would be superfluous.


Sugar rots teeth, and as we’ve seen, most fruit is loaded with sugar.

It could be argued, and I do argue, that any food that rots teeth isn’t meant for human consumption, that we have not evolved to consume it and remain healthy. Mainstream health authorities mostly deny this. But rotten teeth can be a serious health problem if untreated, leading to abscesses, pain, even death from septicemia, so evolution would certainly select for the ability to maintain healthy teeth. The fact that we can’t maintain healthy teeth today absent specialized care and treatment speaks volumes for the suitability of our food.

Fruit juice may be especially harmful in this regard, and it’s harmful in more ways than that.


Fruit has lots of fiber. Don’t we need that?

Not really; in any case, it’s highly overrated.

Vitamin C

One of the few vitamins in which animal foods are relatively low is vitamin C, and fruits do contain vitamin C. However, a number of vegetables, such as red chili pepper and broccoli, contain more vitamin C than oranges.  So it’s not necessary to consume fruit to get abundant vitamin C. Besides vitamin C, fruit contains little in the way of other vitamins and minerals that can’t be found more abundantly elsewhere.


Humans likely did not evolve to eat much fruit, certainly not year round and not in the abundance that we do today. Further, whatever fruit that early humans did eat was lower in sugar than modern fruit.

Even in the modern era, it wasn’t until after World War I and the spread of modern refrigeration that people ate lots of fruit. Before that, fruit was seasonal and much of it (apples) was used to make alcohol.

Modern fruit is loaded with sugar, is low in protein, and appears to provide not a lot of added benefit compared to other foods.

Fruit isn’t necessary or even particularly beneficial, and certain aspects of it could be harmful. I rarely eat it.

PS: A healthier thing to rather than eating fruit is Dumping Iron.

PPS: Check out my Supplements Buying Guide for Men.

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Dietary Protein Strengthens Bones

Osteopenia – a decrease in bone mineral density – and osteoporosis – the pathological loss of bone density – are common debilities in old age, and sometimes even in not so old age. Both mean and women are susceptible to bone loss, but it strikes women more often. Loss of bone density leads to broken bones, debility and weakness, and hospitalization. A broken hip is often a one-way ticket to death. However, a little-known fact is that dietary protein strengthens bones, so bone loss can be avoided.

Dietary protein strengthens bones

Fracturing a hip is perhaps the most serious consequence of osteoporosis. Mortality from hip fracture at 12 months is about 30%. The incidence of hip fractures is around 600 per 100,000 people per year; that’s all people, not just the old.

Bone density and strength are the most important determinants of fractures.

People who don’t get enough protein are much more likely to have thin, weak bones.

 Lower protein intake was significantly related to bone loss at femoral and spine sites (p ≤ 0.04) with effects similar to 10 lb of weight. Persons in the lowest quartile of protein intake showed the greatest bone loss. Similar to the overall protein effect, lower percent animal protein also was significantly related to bone loss at femoral and spine BMD sites (all p < 0.01) but not the radial shaft (p = 0.23). Even after controlling for known confounders including weight loss, women and men with relatively lower protein intake had increased bone loss, suggesting that protein intake is important in maintaining bone or minimizing bone loss in elderly persons. Further, higher intake of animal protein does not appear to affect the skeleton adversely in this elderly population.

Furthermore, non-animal protein intake showed no relation to bone loss after adjustment for other factors. Only animal protein appeared protective against bone loss.

Contrary to expectations, elders with animal protein intake up to several-fold greater than the RDA also had the least bone loss after controlling for known confounders. Nonanimal sources of protein were not related to BMD. These results suggest that typical population intakes of animal protein, within the range commonly consumed, do not result in bone loss. Rather animal protein intake appears important in maintaining bone or minimizing bone loss in elderly persons.

Older people typically do not eat enough animal protein, and one of the reasons is that the health establishment has told us over the past several decades to avoid meat and other sources of saturated fat.

With this result on bone mineral density, we can add another reason to the list for red meat being a health food.

Resistance training strengthens bones

Resistance training, i.e. weightlifting, strengthens bones.

Naturally, lifting weights is thought of mostly in terms of making muscles stronger, but it strengthens the entire body, including bones, as well as the heart and the rest of the cardiovascular system.

Any weight-bearing exercise will help strengthen bones, and since weightlifting is the weight-bearing exercise par excellence, it’s the best in that arena.

Vitamin D levels are an important determinant of bone mineral density. Getting more vitamin D through sun exposure or vitamin D supplements can help.

Vitamin K is very important for bones, and supplements can provide a good amount, since it’s difficult to get in food. Grass-fed dairy, such as Kerrygold butter, contains relatively large amounts of vitamin K. (Added this paragraph after a valued commenter asked me about vitamin K; I’d forgot.)

Serum ferritin (iron) is associated with lower bone density and a greater risk of fractures in older women.

Calcium supplements, widely used either independently or under a doctor’s advice, are ineffective and may actually increase the risk of fracture. Furthermore, calcium supplementation is associated with an increased risk of heart attack.

Calcium supplements (without coadministered vitamin D) are associated with an increased risk of myocardial infarction. As calcium supplements are widely used these modest increases in risk of cardiovascular disease might translate into a large burden of disease in the population. A reassessment of the role of calcium supplements in the management of osteoporosis is warranted.

Calcium is on my list of supplements to avoid.

Osteoporosis and fractured bones are not inevitable.

Attention to protein intake, the right kind of exercise, vitamin D, and body iron stores can lessen the risk of broken bones.

PS: To be healthy as you get older, check out my books, Muscle Up, Stop the Clock, and Dumping Iron.

PPS: Check out my Supplements Buying Guide for Men.

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Obesity and Aging Are Linked

A just published paper makes the case that carbohydrate restriction with high-intensity interval training is the optimal combination to treat metabolic disease. Let’s take a look at why this combination makes the optimal lifestyle intervention to fight aging too, because obesity and aging are linked.

Obesity and aging are two sides of the same coin

Obesity and aging are quite similar; many health markers that change with aging are related to the same metabolic markers that change in obesity.

In healthy young people, markers of biological age increase from age 26 to age 38. Aging is apparent even then.

The markers that change (increase or decrease) are very similar to those that change with obesity. Hemoglobin A1c, cardiorespiratory fitness, waist-hip ratio, BMI, triglycerides, blood pressure, and HDL all change in aging as they do in obesity. See chart below.




Calorie restriction is the most robust and reliable anti-aging intervention, although intermittent fasting and a ketogenic diet may perform just as well. Based on those facts, it’s not hard to see why obesity and aging are related: less food (or less carbohydrates) leading to leanness and longer life; more food (or more carbohydrates) leading to obesity and shorter life.

Cancer is the second leading cause of death in the U.S., and is highly correlated to both aging and obesity. Some 90% of cancers occur in those over the age of 50, and about 50% in those age 70 or more. At the same time, obesity is responsible for about 40% of all cancers. Similar comparisons could be made with heart disease, diabetes, and a host of other health problems.

Virtually all of the health conditions associated with aging have insulin resistance as a component, just as obesity does.

Good insulin sensitivity is critical for health, and is inherent to being lean and muscular.

Staying lean and muscular as you get older

As I’ve written about ad infinitum on this site, as well as in my books, eating a diet of whole, unprocessed foods, with no added sugar, seed oils, or refined carbs, is essential to staying healthy, and essential to staying lean as you get older.

For staying muscular, strength training, which involves some form of resistance training, is the way to go. Like what I did today:

I’m 62, not that old, and what I did in the video above is certainly not setting any world records, even for my age. But few men or women are doing anything that strenuous. They’re being passive and sedentary, and getting old and fat.

Anyway, back to obesity and aging.

As the review mentioned above makes clear – and again, as I’ve discussed a lot – high-intensity interval training (HIIT) is one of the most effective ways, in addition to weight training, to get and maintain good insulin sensitivity. In literally a few minutes every other day, HIIT can get you as fit as spending 45 minutes a day doing moderate-intensity continuous exercise (MICT, cardio, or aerobics).

Add carbohydrate restriction and you get instant benefits for insulin sensitivity. A mere three days of a very low carbohydrate ketogenic diet can massively increase insulin sensitivity.

Fasting insulin is a very good measure of insulin sensitivity. (Other tests, like a glucose tolerance test with insulin also measured, are somewhat more accurate, but time-consuming and expensive and probably don’t add that much more value to the information you get from a fasting insulin.) My lifestyle of low-carb, whole-food eating, weightlifting, and a bit of HIIT gives me a fasting insulin of 2.9, which I’ll assert is in the low single-digit percentile for my age, or anybody’s age possibly.

Staying lean and muscular in aging: all there is to it?

Certainly people age even if they’re lean, even if they train for strength. I don’t want to give the impression that there’s nothing more to it. Even the fittest are going to die at some point.

What else can you do to retard aging as much as possible, and live to a time of technologies that reverse aging/

  • fast intermittently
  • ensure good vitamin D levels
  • dump iron
  • avoid seed oils like the plague, and ensure adequate omega-3 intake
  • avoid sugar
  • drink moderately (if you drink)
  • don’t be sedentary (even if you exercise)
  • sleep well

I’m probably forgetting a few things here, but if you do them, and follow the diet and exercise plans I recommend, you’ll be doing about 99% of everything necessary to fight both aging and obesity.

PS: For more on this topic, see my books Muscle Up, Stop the Clock, and Dumping Iron.

PPS: Check out my Supplements Buying Guide for Men.

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Do Calorie Restriction, Fasting, and the Ketogenic Diet Have the Same Anti-Aging Effect?

Calorie restriction (CR) is the most robust and effective life-extension intervention known, and intermittent fasting shows great promise in life extension as well. (I’ve written extensively about both calorie restriction and intermittent fasting on this site.) The question, unanswered so far, is how they work, although many possible explanations have been offered. Many pieces of evidence point towards the production of ketones as being the underlying, unifying factor, in which case calorie restriction, fasting, and the ketogenic diet have the same anti-aging effect.

Ketones mimic effects of calorie restriction

Ketogenic diets extend lifespan in lab animals. Does this diet extend lifespan through the same mechanisms as CR and fasting?

Consider that a reliable outcome of CR is the production of ketones. Intermittent fasting also results in ketone production, in fact, larger than calorie restriction. Obviously, ketogenic diets produce ketones also.

Ketone bodies mimic the effects of calorie restriction. Ketone supplements do much, if not exactly, the same thing as a ketogenic diet. Ketones lower insulin signaling and blood glucose, key elements that have been shown to affect lifespan in all kinds of lab animals from yeast to C. elegans (a worm) to rats.

One of the biochemical pathways thought to be crucial in aging is mTOR (mechanistic target of rapamycin). The ketogenic diet inhibits mTOR. Whether it inhibits it to the same degree of CR or fasting isn’t known; likely much more research would be required to find out.

The ketogenic diet stimulates mitochondrial biogenesis, as does CR and fasting. It lowers oxidative stress by upregulating antioxidant defense mechanisms. The ketogenic diet stimulates autophagy.

The ketogenic diet is well known to result in loss of excess body fat, as are CR and fasting, and reduction of excess body fat is thought to be a major mechanism of CR in lifespan prolongation. This aspect gives me a little pause in the comparison, because it’s possible that, while ketogenic diets help fat loss, they don’t universally decrease it to low levels. It’s perfectly possible, although perhaps difficult, to gain fat mass on a ketogenic diet.

What accounts for effects of CR

Are the effects of CR due to reduced calories in general, or reduced protein, carbohydrates, and fat? Or maybe CR is just a form of fasting, since animals on CR eat all their food at once.

Between 70% and 100% of the effects of fasting are due to carbohydrate restriction.

The lower figure, 70%, comes from a study in diabetics in which they either fasted or ate a VLCKD (ketogenic diet) for 3 days. One could argue that had the experiment used a longer time period, the values for fasting and ketogenic diet may have converged, since benefits of zero carbohydrate intake usually take longer than a few days to manifest completely. (Although the study did show that you get instant benefits by restricting carbohydrate.)

The higher figure, 100%, comes from a study in which volunteers either fasted or fasted with a lipid infusion that gave them all their caloric requirements. There was no difference between the groups in plasma glucose, free fatty acids, ketone bodies, insulin, and epinephrine concentrations, which led the researchers to conclude: “These results demonstrate that restriction of dietary carbohydrate, not the general absence of energy intake itself, is responsible for initiating the metabolic response to short-term fasting.” However, the researchers seem to have missed the fact that neither group of volunteers consumed any protein either, so their conclusion seems premature.

Many scientists in this field place great emphasis on protein restriction as important, for instance Valter Longo and his fasting-mimicking diet. However, recent experiments have found no effect of protein restriction on the metabolic and biochemical parameters affected by CR. Some data shows otherwise, but this major series of experiments by John Speakman and colleagues, and their null results with regard to protein restriction, cast serious doubt on the idea that it will prolong lifespan. For what it’s worth, in my opinion protein could be important, but distinctly second in importance to restricting carbohydrates.


Fasting and CR have a great deal in common with the ketogenic diet, with many overlapping if not identical effects, including the extension of lifespan.

Is it even necessary to restrict calories or fast, or does one need merely to follow a ketogenic diet? While CR and fasting may offer benefits beyond the ketogenic diet, it seems probable that the ketogenic diet gets you at least ~90% of the benefits of CR and fasting.

PS: For more on extending your lifespan, check out my book, Stop the Clock.

PPS: Check out my Supplements Buying Guide for Men.

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