This week, several people have asked me to comment on a recent analysis (no abstract, buy the full text, fucked up) about an interesting case. It was about a 51-year-old woman who, after starting to train for a marathon on an extremely low-calorie (according to her) diet, not only did not lose weight, but seemed to gain it. At the same time, the metabolic rate decreased by about 30% compared to the forecast.
By increasing her calorie intake, her fat percentage dropped and her metabolic rate increased. Actually, without further details, such a case is not easy to comment on. We are talking about an elderly woman (at or after menopause) taking some kind of antidepressant, we know about the calorie content of her diet only from her words, and the way to measure the percentage of fat was, at best, problematic (bioimpedance analysis). During menopause, strange things happen to the metabolism, some medications have side effects, self-calorie counting can be terribly inaccurate, and bioimpedance analysis is also far from perfect. Still, measurements of changes in metabolic rate are quite curious, and suggest that something is happening.

In other articles, I have already mentioned one oddity that I have personally dealt with and observed over the years, this is when the combination of too much calorie deprivation and very high volume of training (especially high-intensity activity) can lead to the fact that weight loss either slows down or stops altogether. This is one of those oddities that occurs much more often than one might expect. There isn't much research on this topic, but I'm happy to share my speculations with you about what might be the case in these cases.
I also want to note that the combination of a significant deficit and a large volume of loads does not lead to disastrous consequences for everyone. Some get away with this, but for many, the return is extremely unpleasant.

First, a little history

When I was in my early 20s, I had a very specific client. She was a little, well, frankly, nuts. I'd say she was post-menopausal, but I'm not 100% sure. In any case, she started working with me, hoping to lose weight, and very quickly. slipped into something like 2 hours of cardio a day and cut calories to the limit. According to her, she ate 600 kcal a day, and I won’t even try to describe her diet - she was absolutely idiotic (breakfast, for example, consisted of half an egg, and I’m still not sure how you can eat half an egg).
At that time, I already had a vague suspicion that too much training and too low-calorie diet is not a good combination. For weeks, I urged her to either cut back or add calories. She persisted; how can it work? I tried to point out to her that what she had been doing so far wasn't working either, and if she tried to do something else, it certainly wouldn't get any worse, but the logic didn't work in this case.
In general, at some point she went either on vacation or on a cruise. And what do you think she did? I trained less and ate more, as everyone does on vacation. And she came back a couple of kilos lighter. “See, see,” I told her, “you ate more and exercised less, and a good thing happened.” But she immediately returned to her huge deficit and over-training. Well, it happens sometimes.

Later, when I was about 30, I fell into the same thing when I was on the Bodyopus program (probably this one experience taught me what NOT to do in the process of losing weight). Frustrated by the stalled weight loss (for starters, I had already been on a diet for too long by this point), I began to exercise even more and cut calories. This, combined with the really terrible "carb loading", brought the weight loss to a complete halt.

In addition to these cases, I see this phenomenon all the time, for example on my forum, when people (usually women, but not always) try to combine a significant caloric deficit with high training volume (plus, these workouts are often high intensity).). And nothing happens. And if I manage to persuade them to reduce their activity (or at least the intensity to some acceptable level), the process inevitably starts to go better.

What's Happening: Let's Talk About Cortisol

I believe that each of you has heard about cortisol - this is one of those hormones that there are many misconceptions about. Simply put, cortisol is a stress hormone that is produced in the body in response to almost any type of stress. In the fitness/bodybuilding world, cortisol has an extremely negative reputation (cortisol is "bad" just like thyroid hormone or testosterone are "good"), although this is an oversimplification and inaccuracy.
Whether cortisol does good or bad in the body depends on how it is produced. In principle, sharp peaks of cortisol are rather beneficial, but a chronic increase in its level can lead to trouble.

For example, the morning peak of cortisol promotes fat mobilization. In contrast, chronically elevated cortisol (especially in the presence of elevated insulin) contributes to the accumulation of visceral fat. A non-fitness moment - a spike in cortisol improves memory (which is why we remember stressful situations in such detail), while chronically elevated levels (which often occur during depression) sink our memory to the floor. There are many more aspects where cortisol peaks are beneficial, and chronically elevated levels are even the opposite.

Either way, dieting is stressful. And training is also stressful. And the more extreme version of both you stick to, the more stress arises. And I suspect that a lot of what happens when people try to combine a big calorie deficit with killer workouts is the effects of skyrocketing cortisol levels (there's another aspect that I'll get to later). In general, you get that chronically elevated cortisol level.
By the way, this is another reason why I suspect that different types of cyclic diets help with some of these problems. When calorie levels rise to maintenance levels or above, even if only for a short period, you are lowering diet and exercise-induced elevated cortisol levels. This, of course, if you do not get wild stress from the very fact of increasing calories, but here I am getting ahead of myself. (Who knows the underlined phrase, huh?)

So why is it bad?

As already mentioned, chronically elevated cortisol can lead to a lot of trouble. One of them is the banal fluid retention, which can mask weight loss for a while, sometimes for a very long period. Reducing training volume, or training frequency, or intensity, as well as increasing calories The diet lowers cortisol levels and helps get rid of this fluid.
But that's probably not all. Another effect of chronically elevated cortisol levels is leptin resistance in the brain. When the normal leptin signal to the brain is blocked, a lot of things can go wrong with the metabolism, and I suspect this is part of the problem.

On a related note (albeit not related to cortisol per se), in at least one study, an additional 6 hours of aerobic exercise on a very low calorie diet (mostly consisting of the minimum required amount of protein) resulted in a much greater decrease in metabolic rate, than just a diet. It seems that the body monitors the availability of calories (banal calorie intake minus consumption) and if you go into the negative too much, problems begin.
That is why I am strongly against too much cardio on the Rapid Fat Loss program (very low calorie diet); they will do more harm than good. The main source of trouble is invariably cardio - when people ignore my recommendations, add a ton of cardio and fat burning stops. (Has anyone else gained weight on programs like Insanity while following the perfect diet and training schedule?)

In general, there are some fairly plausible mechanisms by which the combination of an aggressive calorie deficit and high training volume creates problems. Whether it's fluid retention caused by cortisol, or a drop in metabolic rate due to leptin resistance, or something else, but, in any case, something has a place to be. From a practical point of view - for many, this combination simply does not work. But, I must say, some people still get away with it. But not everyone.

Additional factor

There is another factor whose influence I have noticed over the years of studying this problem. As strange as it may sound, it has to do with personality and character. I've noticed that the people who have the most trouble with the combination of high training volume and a significant calorie deficit tend to be slightly jittery (to put it politely). To put it a little less politely, they are walking stress.

You can almost “hear” the stress in their messages. Every post is full of exclamation marks and feeling desperate "I HAVE TO LOSE WEIGHT RIGHT NOW!!!!!". If weight loss stops even for a day, they go crazy and want to cut calories and add another hour of cardio. You can almost "see" their tension as they sit and pound on the keyboard looking for a solution.
And this is a problem, because such comrades are already prone to increased secretion of cortisol. There is also such a really strange thing as the problem of amenorrhea. It is generally thought to be associated with a low fat percentage or low calorie intake. But amenorrhea is often