Here is a brief retelling of the interview of Alan Aragon. Lyle McDonald about the concept of “metabolic damage”. Published in the AARR (Alan Aragon Research Review) for April / May 2013.
The subject of the interview was formulated by Aragon in the following form: “The main question I want to ask you is related to the concept of “metabolic damage”. Trainers and competing (and not only) bodybuilders (mostly women) often talk about cases when consuming a very small number of calories (that is, in the range of 700-1000 kcal per day), in combination with large amounts of cardio (i.e., 2 + hours per day), observe no weight loss effect. Do you think about this, and how realistic is it and / or what mechanisms underlie it this observation?“
As you know, the adherents of “metabolic damage” claim that after a “fall” of metabolism, you will at least not lose weight, and you can even begin to gain it even on a deficit, and after leaving the diet, you will have to spend several months on restoring the “killed” metabolism.
The truth about metabolic damage
The sense of this phenomenon
We need to talk not about “metabolic damage” but about the body’s natural metabolic adaptation to diet because the body does not care about our desire to look good (in this context, to lose weight), the body wants to save us from starvation.
On a diet with abnormal physical activity, the hormone cortisol is very much to blame:
- cortisol causes water retention;
- calorie deficiency (diet) increases cortisol levels;
- cardio load increases the level of cortisol;
- stresses increase the level of cortisol (losing weight is generally in a lot of stress, including worries about the speed of weight loss);
- and close the “Möbius strip,” say again: cortisol causes water retention.
When the levels of cortisol go off scale and begin to “splash over the head,” and the amount of water drawn by it also reaches its next peak, the losing weight person instead of stopping and thinking (what’s the reason that the weight stuck and even growing. I eat almost nothing and do a lot of fitness?), does everything the other way around. He reduces calorie content even more and adds physical activity (mostly talking about cardio, it’s usually the case with losing weight girls) and achieves even worse results, according to the reasons described above (basis – cortisol).
And as soon as those who are losing weight release their reins and increase their calorie content, reduce cardio, after a couple of days high cortisol levels finally begin to normalize, and the body gets rid of accumulated water, and the arrow on the scales rapidly flies down, “magic” / “magic whistle»/ LTDFLE. But in fact, no magic, everything is simple, cortisol down, water to drain, but this is not a decrease in body fat.
There is no escape from another important hormone – leptin.
As you know, leptin is a hormone, it signals to the brain about the energy reserves in the body (and how much you eat), and when it falls, it causes much of what is often incorrectly called the “starvation response” or “metabolic damage.” But in reality, this is neither one nor the other, but a natural metabolic adaptation of the body to a diet.
A drop in leptin levels causes a lot of things:
- metabolic rate slows down,
- hunger increases,
- lethargy appears,
- thyroid function decreases,
- testosterone falls,
- a whole bunch of other interconnected shit happens.
So, interestingly, cortisol, in addition to its other properties, causes leptin resistance in the brain, which means that leptin cannot fully deliver the corresponding signal to the brain. It means that the higher the levels of cortisol (low-calorie content, a cloud of cardio, stress, etc.), the fewer signals the brain receives from leptin, and this is also one of the significant reasons for the ongoing process of inhibition of weight loss.
Total metabolic rate
The determining factors in the overall metabolic rate consist of several parts and are usually divided into the following four categories:
- BMR / RMR (basic metabolic rate),
- TEF (thermal effect of food),
- TEE (thermal effect of exercise),
- SPA / NEAT (spontaneous physical activity / non exercise activity thermogenesis).
All these 4 factors respond to changes in food intake and body weight: for example, as soon as you start a diet, TEF automatically decreases slightly, since you eat less food (note that this has nothing to do with the frequency of meals).
BMR goes down as you lose weight because the body burns fewer calories. Thus, with less body weight, you also burn fewer calories in training (by the way, you can increase the total energy consumption by artificially increasing body weight: for example, use a vest with weighting agents, etc.).
Again, many factors influence the SPA / NEAT indicators. You are generally less active on a diet, the body tries to make less unnecessary gestures, lethargy, etc. appears, which ultimately allows you to burn fewer calories per day.
The adaptive component of metabolic rate reduction
There is such a not very well-known moment, as the adaptive component of metabolic rate reduction.
As an example, McDonald cites the following, “… suppose someone is losing twenty pounds, and, based on all mathematical calculations, one would expect a 10% drop in metabolic rate. But when you measure real indicators, then, in fact, a decrease in metabolic rate by 15% is detected. That is, the drop in metabolic rate is greater than what you set based on the drop in body weight. This additional 5% is the “adaptive component of metabolic rate reduction.”
And this is usually due to the hormonal response: a drop in leptin, a decrease in the level of thyroid hormones (the conversion of T4 to T3 on a diet is nullified), a drop in the activity of the sympathetic nervous system also adds its drop (partly, the ECA stack helps to compensate for this drop).”
Self-deception, violation of dietary discipline
The constant hunger that is present on diets (especially low-calorie ones) causes uncontrolled episodic breakdowns and “glitches” (about which people sitting on diets of 1200 or less kcal and crying about gaining weight at such a calorie content or suspension, try, as a rule, not to talk about), which can completely negate all the efforts and actions of losing weight and compensate for the deficit created within a week.
The pivotal question
Can a drop in metabolic rate, due to a drop in body weight and an adaptive component, ever be enough to fully compensate for the true loss of fat?
Over the past 80 years, human studies have not supported this conclusion.
Existing studies about the decrease in metabolic rate (whether due to weight loss or an adaptive component), never (!) confirmed the excess of the actual deficit, whether it be about men or women.
Fat loss can slow down (if you create a 30% calorie deficit and your metabolism slows down 20%, then your real deficit is only 10%), but this was never enough to either completely stop fat loss (and even more so, in order to start gaining fat under these conditions).
What is really going on?
According to McDonald, these problems occur in dietary neurotic crazy people who rely on inaccurate information about food consumed (do not forget about unaccounted for breakdowns and glitches), which have unrealistic water retention in the body, combined with low-calorie content diet and an unrealistic amount of cardio training, and which “magically” begin to lose fat again when their poorly controlled 1200 kcal becomes well controlled 1250 kcal.
Additionally, see how complete diet breaks can boost your cutting.
What is more, why not read how to keep muscle tissue while on a diet?