And let’s go back to talking about calorie restriction and longevity: the theory that restricting calories would increase longevity in living beings is fascinating. According to this theory, which I believe has been studying for no less than seventy years (Ancel Keys’ studies in this regard date back to the 1940s), if one lived natural life while eating fewer calories than our body needs in terms of requirements daily calorie, you would live more. In short: slowing down the metabolism (which is what it is) would be the way to have a longer life.

To give substance to this theory, a new study appeared in Nature : indeed, as soon as I read it I realized that there was nothing new in reality, because the data analyzed were those of two previous studies on the effectiveness of restriction caloric levels in rhesus monkeys (macaques). In one study it was established that the monkeys had achieved greater longevity by following a low-calorie diet for life (we will call it, vulgarly, a positive study); in another that there was no positive association between caloric restriction and longevity of the monkeys (negative study).
Previously, calorie restriction studies have been done on yeast , mice of a certain species and fruit flies. Again, with mixed results.

But back to the macaques: the University of Wisconsin scholars pointed out that due to the differences between macaques (always macaques but of different races), due to the differences between the macronutrients in the diet (same calorie density but different distribution between carbohydrates, proteins and fats) and for the differences in the type of diet (natural in the positive study, “semi purified” or I guess laboratory, in the negative study), for the differences in meal timing, for the differences in the age of the monkeys, it was normal to expect different results between the two studies. I would say no, that is, if you speak of simple calorie restriction as a necessary and sufficient condition to establish greater longevity, the distribution of macronutrients, the specific diet or the race does not matter. What matters is that you have found a human-like species, and that for so many calories you can prove to me that that species lives longer. Can’t prove it? So, it means that there is almost nothing new on the horizon. In fact, in neither of the two studies analyzed was there a collection of data on longevity, but only on survival.

That food restriction may be a key to reducing chronic disease risk is an interesting hypothesis; but currently this restriction is not just caloric . But of proteins or some amino acids, of hours of food intake versus the hours of fasting, of carbohydrate restriction. As you can see, there is a broad spectrum of possibilities . Telling people that they need to eat less and diet their entire life seems like a gross oversimplification, and one that can lead to unpleasant consequences. Calorie restriction isn’t for everyone. The harms of a slow metabolism aren’t just about a little hypothermia or a drop in libido.
Looking forward to more concrete and long-term studies on humans, on human beings who live and get stressed and are not monitored in a laboratory, it is naive to think that it is enough to review the studies on monkeys to sum up at the expense of our health.