The Most Important Anti-Aging Advice

Once when I was talking to someone about my book on aging and the actions that we can take to slow it, this person asked me what was my most important piece of anti-aging advice, if I had to put it in one sentence.

My reply: “Stop eating all the time.”

This piece of advice is also important when it comes to staying lean and/or losing fat.

Eating and Aging

The most robust (non-genetic) intervention known for prolonging the lifespan of lab animals is calorie restriction (CR). Animals that have their food restricted from 10 to 50% of that of fully-fed animals live much longer, in some cases 50% longer.

Many theories have arisen as to why CR increases lifespan. One theory is that CR results in less fat tissue, and that this is crucial to longer life.(1) Other theories have to do with repressed insulin signaling (2) and/or increased autophagy, the cellular self-cleansing process that rids cells of junk.(3) Likely all of these theories are related to each other mechanistically — you can’t have greater autophagy without reduced insulin signaling, which in turn leads to lower fat mass, for example.

I like to focus on autophagy, because this is a marker within our control to some extent.

Aging is characterized by a decline in the amount and amplitude of autophagy, which allows increased amounts of cellular damage and junk to accumulate.

Autophagy is strongly cyclical, rising and falling over periods of hours and days. Eating strongly decreases autophagy, and fasting increases it. I hope you see where I’m going with this.

If aging means less autophagy and more damage accumulation, and fasting increases autophagy, then fasting fights aging.

In fact, intermittent fasting is the most potent anti-aging strategy available.

Now, if we eat all the time, we never enter the fasting state and never up-regulate autophagy.

Eating constantly or every few hours, or “grazing” as it’s called, is one of the most potent pro-aging actions available.

So stop eating all the time.

How often does eating have to be to constitute “all the time”?

To answer that, it’s helpful to look at what people did in the old days — you know, about 40 years ago, before the obesity epidemic started. Or even more so, before the era of industrial processed food and cheap fast-food restaurants.

It was common for people to fast for 12 hours daily, from dinner in the evening until breakfast the next morning. Many mothers often told their children, “Better eat your dinner because there won’t be anything until breakfast.” My mom did anyway.

As we age, insulin resistance increases, fat tissue accumulates, and autophagy declines.

But we can fix that to a great extent by fasting longer than 12 hours. By 16 to 18 hours, autophagy proceeds at a rip-roaring pace, clearing out damage making cells young again.

Eating and Obesity

Obesity likely has many causes, all working together to produce it.

But one factor that doesn’t get enough attention is the frequency with which we eat. When we eat constantly, insulin never drops by much, and so lipolysis, the exit of fat from fat cells, can’t take place.

Contrary to popular belief, energy expenditure has not decreased in recent years and is similar in modern people to that of wild, non-overweight, mammals.(4) Westerners seem to expend the same amount of energy as hunter-gatherers.(5)

Hunter-gatherers of course eat different food from Westerners, but they also don’t eat all the time.

Furthermore, energy expenditure can increase with fasting.(6)

And our distant ancestors way back in the 1960s had a far lower rate of obesity while eating, in general, lots of crappy food. They weren’t interested in “health food”, but largely managed to keep obesity at bay anyway.

The lesson is clear, to stay lean and/or lose weight, stop eating all the time.

Current mainstream advice on losing weight seems to be to eat constantly in order to keep your metabolism up. (I say “seems to be” because I avoid reading mainstream health advice where possible — most of it is bad for health.)

In fact, the admonition to eat constantly, or graze, is the kind of BS weight-loss advice that’s perpetuating the obesity epidemic.

Can you really lose weight by eating more often? No, you can’t. Not only will someone who eats constantly fail to lose much weight, but he’ll promote aging and the diseases that go with it.

PS: Check out my Supplements Buying Guide for Men.

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  1. Laguna Beach Fogey says:

    At my leanest, I ate twice a day within about a 6 or 7 hour window in the morning and afternoon. No snacks. In my experience, convincing people of the efficacy of CR and intermittent fasting is uniquely difficult. There’s a lot of propaganda out there telling people that they should be constantly snacking.

    • Allan Folz says:

      I humbly submit Folz’ Iron Law of Health Intervention:

      The efficacy of an intervention is inversely proportional to its 3rd party financial benefit.

      Fasting > Potato Hack > DIY Paleo (Full-fat dairy, eggs, gr. beef) > Weight Watchers & “diet bars”
      Pull Ups > Dumb Bells > Treadmill/Stairmachine > Yoga Classes
      Noon day sun > Vitamin D drops > Dietary Supplements (NAC/Glycine/Resveratrol/etc.) > Statin

      • Allan Folz says:

        Dennis, you want to make that yours on teh twatter, be my guest. It is my gift to you. 🙂

        Mangan’s Iron Law of Health Intervention has a nice ring to it, if I do say so myself.

        • Heh says:

          Iron Law of Health Intervention:
          If you say, “Don’t do X, it’s bad for you”, you will get one of the following responses:
          1. My grandpa did X his whole life and lived to be 100.
          2. Too hard, I can’t live without my X.
          3. Gummint Science says X is good for you.

        • P. D. Mangan says:

          Thanks, Allan! Great formulation. I’ve said before that as regards supplements, a rule of thumb is the more expensive they are, the less you need them.

    • José Carlos says:

      Even worse, most, if not all, nutritionists keep telling you the same. “Eat every three hours.”

  2. José Carlos says:

    Hi P. D.

    Can you still read French? I hope so. This article (see the link) agrees with your post on many points.

    grignoter (French) = to graze (English)

    • P. D. Mangan says:

      Thanks José Carlos. I could make out some of that, been a long time since I’ve read the language.

  3. Ted says:

    The more I read, the more I think it’s all about AMPK. All the usual suspects activate AMPK – fasting, exercise, reservatrol, sulfarophane, curcumin etc, then AMPK in turn activates autophagy etc

  4. Shitlord Byron says:

    I’ve done the intermittent fasting thing for a decade, and I’m slim and at 40 I literally look 10-15 years younger than I am. I don’t exercise much, except for cycling a few miles to work and some moderate lifting once or twice a week. I also smoke at least a pack of cigs a day and drink at least a 5-6 drinks, and eat pretty much whatever I like.

    • Christopher says:

      That is kick ass Shitlord! Are you able to elaborate on your IF routine during a standard week? Also, I love and smash beers way too much. The 5-6 drinks you refer to, what type are they and is that daily consumption?

  5. Charles says:

    Hi Dennis,

    Given that, as you write, “our distant ancestors way back in the 1960s had a far lower rate of obesity while eating, in general, lots of crappy food”, how would you rate the importance of pursuing a low-carb diet combined with 12+ hr fasting periods as opposed to *just* not eating all the time with no regard for carb/fat/protein intake? How much of a difference does abstaining from crappy food actually make in either dietary context?

    I”m a casual reader, so I apologize if this has been answered elsewhere.

    • P. D. Mangan says:

      Charles, that’s a good question. Some populations, e.g. in Japan and China, have subsisted on large amounts of white rice and were not fat. I really doubt they did a lot of midnight snacking. From that you could say that the fasting period is very important. On the other hand, some of the foods we have are so calorically dense that to my mind they all but negate fasting. A frappuccino, for instance, or mac and cheese, you get the idea.

  6. bILLYpILGRIM says:

    Wont there be any negative effects of autophagy? With billions of cells disgorging waste into the lymph system, then on to the kidneys, can’t it overload the system? The lymph system is a circulatory system – it just doesn’t have a dedicated pump.
    Sure, we need lots of water, maybe one of those decongestants that make mucus more viscous. Theprogram has helped me drop a lot of fat, but I do wonder if there aren’t consequences.


    • P. D. Mangan says:

      Billy, the waste from autophagy is recycled, e.g. protein is broken down to amino acids, cellular organelles to their constituent fats and proteins, etc. The components of what’s being broken down are therefore not waste products, in the sense that, say, urea is. From this fact you can see why fasting increases autophagy, since one of its main purposes is to supply the body with nutrients when it isn’t getting any from outside. Fat can be broken down, glycogen too, but to get amino acids — and the body always needs some minimal amount around — it must break down proteins.

  7. Graham says:

    Hey PD,

    I just wanted to get your thoughts on something that I’ve been pondering for a while regarding intermittent fasting.

    I fast pretty much every day, as per your recommendations, on most days for something like 16 hours. Although some days it is more like 12. I don’t have any problems with hunger while fasting which is lucky and I enjoy doing it knowing that I am doing something good for my body.

    I do however have relatively mild but persistent hayfever. What this means is that throughout the day I am often swallowing saliva and occasionally flem (sorry if this is making you feel a little nauseous). I wanted to have your opinion on whether you think this is likely to be having an impact on my levels of autophagy?

    Obviously my aim when I fast is to induce autophagy, and to do so as strongly as possible. Ideally I would like to avoid anything that might hinder this aim. Not sure what I could really do to prevent this though if it is having an impact on my levels of autophagy. Thanks love the site.

  8. garymarHIT says:

    PD said, “I really doubt they [Japanese and Chinese] did a lot of midnight snacking. ”

    The Japanese have an old proverb, “Hara hachibunmeni isha irazu”, which means “Eat to 80% full and never need a doctor”.

    In discussions on health blogs you’ll hear people abbreviate it to “Harahachibu”.

    However a lot of modern Japanese don’t follow this advice and just like everywhere else, obesity rates are rising (though still way lower the US).

  9. Christopher says:

    Dear Doctor Magnan,

    I am a fan and convert to intermittent fasting.

    I would be grateful to receive you guidance on the timing for consuming Nicotinamde Riboside when fasting. For example, do you recommend consuming NR at start of fast, middle of fast etc.

    Best regards,

    • P. D. Mangan says:

      Hi Christopher, I believe that NR may accentuate fasting benefits, as does niacin and nicotinamide. So go ahead and take it when fasting. (BTW, I’m not a doctor.)

  10. Johnny says:

    Hey PD,
    Have you looked into capsaicin (found in pepper)? It has been shown to cure/reverse type 1 diabetes, improve insulin sensitivity, activate pAMPK, and kill prostate cancer cells:
    ” Prostate cancer tumors shrank by 80 percent when exposed to capsaicin. Another study found it to destroy lung cancer cells and pancreatic cancer cells without destroying nearby tissue. The capsaicin kills these cancer cells by triggering the mitochondria in the cells to undergo apoptosis, or cell-suicide. ”
    A more comprehensive post on it might be interesting, I suppose you could add it to curcumin etc in the supplements box.
    PS the comment window is too short, can only see 3 lines while typing so inconvenient.
    Thanks for your work, loved the book on iron.

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