The best thing you can do to get and keep a trim body is to pay attention to your body composition, the proportion of muscle and fat your body has. Unfortunately, hardly anyone knows or does this. This article will show the scientific truth behind muscle, fat, and weight loss.

Low-calorie diets don’t work

The most common way that people try to lose weight is through eating less, in other words, a low-calorie diet. This approach has a number of problems:

  1. Eating less can only be pulled off over relatively short time periods; hunger eventually sets in and the person usually returns to eating more. Evolution made hunger a powerful drive, for good reason.
  2. Weight loss by eating less is virtually always accompanied by muscle loss, which is bad for health and leads to greater disease risk.
  3. Eating less lowers the metabolic rate — the amount of calories you burn at rest. A lower metabolic rate, besides making you feel fatigued and cold, also means that weight loss stalls, since the body has adjusted its burn rate lower to match the number of calories taken in. Evolution also made this happen for a good reason, namely to prevent you from starving to death.

Eating less, often combined with “moving more” (more exercise), is an all-around lousy way to lose weight and has repeatedly been shown to be ineffective in the long run.

Recently we discussed the group of people who lost tremendous amounts of weight via eating less and moving more on the TV show The Biggest Losers. The dirty secret of this show is that most of the people who lose weight regain it, and often end up weighing even more than when they started.

The main theory as to why these people regain their weight and then some is that they have permanently damaged their metabolism by consuming less food. Let’s call it, appropriately, the permanent metabolic damage theory. They then get in a situation where it’s virtually impossible to eat less than they burn, and gain weight no matter how hard they try.

Evolution isn’t that stupid.

There’s no such thing as permanent metabolic damage.

My theory is that the Biggest Losers and others who lose weight by eating less and moving more have lost lots of muscle along with the fat. In fact, unless you lose weight the right way, muscle loss is inevitable and comprises between one fourth and one third of all weight lost. That’s a disaster.

Losing muscle is a disaster not just for health, but for maintaining a normal body weight. Muscle is the most metabolically active tissue. Loss of muscle translates into a lower metabolic rate.

This is precisely what happened to the Biggest Losers when they regained weight. (Also, trying to use a low-fat, high-carbohydrate diet for weight loss and maintenance is a contributory factor.)

No such thing as permanent metabolic damage

A new review of the literature on weight loss, regain, and metabolism shows that “body composition [relative amounts of muscle and fat] is the most critical factor in determining absolute RMR [resting metabolic rate] in neutral energy balance.”

Furthermore, ” the theory of permanent, diet-induced metabolic slowing in non-obese individuals is not supported by the current literature.”

In simpler terms, the more muscle you have, the higher your metabolic rate — the rate at which your body burns calories for energy.

Permanent, diet-induced metabolic damage, or a permanently lower metabolic rate due to weight loss, does not exist.

Retaining muscle with age

Obesity is said to be a characteristic of aging, and empirically, it is. But is it an inevitable aspect of aging. No, it is not.

One reason for increasing obesity with age is said to be muscle loss, which almost always occurs when people get older.

Why do we lose muscle with age? One reason is anabolic resistance. When someone is anabolically resistant, muscle does not respond as well to either resistance exercise or protein.

Anabolic resistance is not an inevitable consequence of getting old. It is closely connected to insulin resistance.

So to retain youthful levels of muscle anabolism, get insulin sensitive. Do this by avoiding refined carbohydrates and sugar, and eating a paleo diet. Add weight lifting into the mix.

That will keep your metabolism in good running order, and you’ll feel better and will be much less likely to gain body fat.


There’s no such thing as permanent metabolic damage. There’s only muscle loss.

Anabolic resistance as a phenomenon of aging is way oversold. It’s connected insulin resistance and nothing more.

PS: For how to build muscle, get my book Muscle Up.

PPS: You can support this site by purchasing through my Supplements Buying Guide for Men.

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  1. Chris Nahr says:

    Regarding metabolic rate, I found that the healthiest meals (fat and protein and slow-digesting carbs) leave me feeling hot and stuffed. That would seem like an adverse effect, and you would rather avoid that by consuming “light” meals with fast-digesting carbs that leave you feeling active. But that’s a trap: the “light” meals soon make you hungry again, they felt so light because calories were quickly shuffled off to fat cells. It’s the healthy response to lots of calories to have your metabolism go into overdrive and refuse more food for a while. Counterproductive in an age of easily available simple carbs, and something one must actively avoid.

  2. Mhm says:

    “Low-calorie diets don’t work”

    This is a bit too extreme in its wording.
    It works perfectly, being also known as starvation.
    Of course, as pointed out in the article, it leads ultimately to starving to death, so powerful
    instincts are in place to prevent it.
    But it actually works perfectly.
    If one’s impulse control is powerful enough, one has to not do anything to get slim;
    just doing nothing (instead of eating) achieves full effect.

    • P. D. Mangan says:

      True. Most people don’t have enough impulse control though, and hunger makes for a powerful impulse.

  3. Jd says:


    If I’m on a low cal diet and lifting with weights staying steady, do I need to worry about muscle loss?

  4. Montgomery says:

    A healthy diet and resulting weight loss are also greatly helped by intermittent fasting (IF), if you exploit it smartly:
    IF means a bit of self-starvation, and, especially towards the end of the IF period, hunger surges.
    But not every hunger is the same – the more hunger one feels, the more subjectively desirable and rewarding low-calorie-dense food (LCDF) becomes!

    When we are full, LCDF, like a carrot, is not attractive and therefore avoided; only high-calorie-dense-food (HCDF), like cake, is attractive and therefore eaten.
    The more hungry one becomes, the higher the attractivity and subjective reward from LCDF rises:
    Towards the end of a 24h-long IF a nice bowl of raw carrots “magically” becomes appealing and
    desirable – it just subjectively tastes much better when one is hungry.

    We shun a bowl of broccoli when full, and it tastes bad in this condition,
    but we desire even LCDF like broccoli AND CAN ENJOY IT when we are really hungry after IF.

    This effect is exploitable not only for tricking one’s appetite into eating more healthy vegetables,
    who happen to be all LCDF, but also for weight loss:

    Because LCDF will subjectively appear to be rather desirable after IF because of hunger,
    eating loads of healthy vegetables (I personaly eat one raw head of broccoli) FIRST after IF
    will fill the stomach physically with a lot of LCDFs, therefore preventing any overeating
    right from the start; if you eat this way after IF, you will feel complete satiety much sooner and EFFORTLESSLY reduce your overall caloric intake.

    We might call this IFLCDFF, or so, for “Intermittent Fasting then Low Calorie Dense Food First”.
    (My acronym-forming talent could be better, obviously)

    This works for me (and some friends I made doing it, too) extremely well for quite effortlessly
    eating hypocaloricly and therefore losing excess body fat.
    (In my opinion the caloric budget, aka calories in vs. calories out is still the only proven basis for weight/fat control; IF-LCDFF achieves this just subjectively by much less effort/impulse control).

    • P. D. Mangan says:

      Good idea, Montgomery. As Schopenhauer said (I think he got it from an old proverb), “Hunger is the best sauce.” I must say, eating a whole head of raw broccoli is hardcore.

      • Montgomery says:

        “…eating a whole head of raw broccoli is hardcore.”
        No, actually not so much.
        Just cut it up in bite-sized pieces, wash it and eat it as a snack/finger-food when reading or so.
        One head is around 400 grams, that “fits in” easily – then some cheese or whey, and you will feel
        full for the next hours and have met your protein requirements.
        I eat this at least twice a week and it has become convenient to me:
        There are appetite-influencing mechanisms at work in humans – if something, even if it tasted
        not so nice at first, is registered as having high nutritional or otherwise health-improving value,
        then our instincts regulating what we crave and what tastes bad or good change accordingly (most strikingly observed in pregnant women who, when the fetus drains some nutrients from their “host” bodies suddenly in certain growth phases, often momentarily develop weird and intense desires for certain foods or food combinations, like chocolate+fish, for example).
        I started eating broccoli in some quantity for its proven health-related properties and did not
        like the taste. After the 3rd meal or so I actually started to somewhat enjoy the taste, and now
        have developed even a mild urge to eat it regularly.
        I have the theory that such mechanisms are the reason vegetables as a food source in
        supermarket offerings still exist: Most vegetables deliver few calories, and they just taste not
        so good, at least not when compared with modern foodstuffs like pizza or
        chocolate bars – vegetables still are in demand by some consumers, they do not taste very good,
        cost a lot per calorie – they MUST have some important nutritional or health-related value,
        otherwise nobody would accept the hassle with them.

  5. Each body is different so low carb diet can work for some and not for the others. But it’s true that if you lose lean muscle while you diet (something people often don’t think about), your resting metabolic rate will slow down, making it harder to maintain your weight loss into the future. That’s why resistance training or weight lifting is so important, why exercise is so important combined with dieting. All in all, great read!

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