Do Diets and Intermittent Fasting Help Longevity? Unreliable thesis

Recently, among diets, intermittent fasting is back in vogue with the promise of “losing weight, improving your health and living longer”. Beyond the scientifically unsubstantiated fads proposed by unqualified sources, is there a relationship between diet and longevity? A study that has an observation duration of almost a quarter of a century attempts to provide an answer to this question: 23.5 years on average, with a sample of over 370,000 people, who at the start of the study were between 50 and 71 years old. years. It was conducted by researchers from some US and Chinese universities, who verified, in particular, the effect of carbohydrates and fats on mortality rates.

In totalin the two decades and more of observation, 165,000 deaths occurred and, as reported on the Journal of Internal Medicinethose at greatest risk were those placed at the extremes of low-carbohydrate diets, or with carbohydrates considered to be of poor nutritional quality, with an increase in mortality ranging from 12 to 18%, while those in a diet low in carbohydrates, but without excesses, had a reduction in mortality, even if small, equal to 2%.

How long regards fats, the result was the opposite: the people who had had the regimes with the greatest reductions were also those who had a more marked drop in the risk of premature death: by 18% in general, by 16% for mortality from cardiovascular diseases, and 18% for cancer. Another effect associated with fats was that of replacing them with other nutrients: even just by eliminating 3% of saturated fats and replacing it with isocaloric foods (which provide the same amount of calories) but healthier, we see a decrease in mortality . The effect is also present for carbohydrates considered to be of poor quality, because if they are replaced with vegetable proteins or unsaturated fats, the related increase in the risk of death gradually disappears. All this therefore confirms how changing even consolidated habits can have significant effects, and how much nutrition is really crucial if we want to avoid the main pathologies of age and reduce the risk of death.

If you wanted draw up a general picture, therefore, the best diet to lower the probability of dying prematurely both in general and associated with the two large families of non-communicable diseases that cause the majority of deaths, namely vascular and oncological ones, is the one that does not eliminate carbohydrates altogether, but foresees them in not excessive quantities, while focusing on quality ones, and which instead pays close attention to saturated fats, severely limiting their intake, and introducing vegetable proteins and unsaturated fats. Everything else (including intermittent fasting) is science fiction, i.e. all hypotheses yet to be proven.

What makes credible data is the fact that the effects on people’s health are determined over time, and it takes decades before a habit translates into damage or, vice versa, into protection (and even so it is very complex and difficult to demonstrate the existence of a cause-and-effect relationship, and quantify it). The solutions that associate a diet lasting a few weeks such as intermittent fasting with longevity already loved by Hollywood stars and promoted by many media (and now back in vogue in Italy after the publication of the latest book by the biologist Antonella Viola) are so still to prove. Deciding to follow diets that are still experimental with the hope of having a health benefit could not only prove useless but even harmful (for example, favoring eating disorders, worsening some health indicators). What is important is not only abstinence from food for 16 or more hours a day but above all the quality of the diet in the hours in which one eats and the level of physical activity.

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Agnes Codignola – 8 Maggio 2023