PasseportSanté – Jean-Michel Lecerf, in your book To each his own weight, you mention the major problem with diets: they fail in most cases, and sometimes even make you fat more. Do you think that all the plans are to be put in the same basket?

There are diets worse than others, for example the Dukan diet is frankly unbalanced because it has 3 times the recommended intake of protein, 3 times the recommended intake of salt and it is extremely low in fiber and vitamins. There are diets that are not very unbalanced, the Weight Watchers diet for example is not so bad. But we also have lots of completely outlandish diets: the detox diet, the cabbage soup diet … which are diets of poverty.

Health Passport – In your book, you discuss how weight gain works (the recruitment of fat cells, their proliferation and swelling). The first two stages of the process would be related to different factors, while the last would only be effective when calorie intake exceeds energy expenditure. Does this mean that an imbalance in the energy balance is mandatory to gain weight or lose weight?

To lose weight it is still necessary that at a given moment, people eat less, that there is an imbalance of the energy balance. But the mistake would be to focus only on how much we eat, rather than why we eat. Why do we eat when we are in low spirits? Why do we pull ourselves together all the time? You must first try to find your food sensations and change your relationship with food. However, this is precisely what diets disrupt: it is wrong to believe that a food makes you fat when the problem is global, it is a question of quantity, of physical activity. The case of obesity is special since it is not only a disease of overeating, it is a disease of adipose tissue, and possibly of the intestinal flora. Obese people are not necessarily bigger eaters than others, or they may have been, but they are no longer. We cannot therefore compare a person who has a few extra pounds and a person who has been obese for decades with several diets behind him. In these cases, the goals should be reviewed, because if it is no longer possible to lose weight, it is better to simply try not to gain any more weight.

Restricting yourself, as you do during dieting, results in a reduction in lean mass more than fat mass. When patients gain weight, therefore, they not only get fatter, but fatter. As they regain fewer muscles than they lost, this muscle deficit leads to a decrease in metabolism, and therefore less energy expenditure. Also with age, metabolism decreases, and disabilities increase. Weight and age mean that patients spend less and less and are more likely to gain weight. Finally, there is an inflammatory component in obesity, which will induce insulin resistance, disruption of hunger signals, and leptin, the slimming hormone, no longer works.

PasseportSanté – Can we really speak of an “incurable disease” in the singular? Aren’t there many types of obesity?

There are no two identical obesities, which is why we cannot claim to provide a unique answer, to offer a unique diet for each weight problem. Today, we know more or less how obesity is constituted, but we do not know very well the causes of the obesity epidemic in the world, between the lack of sleep, endocrine disruptors, cesarean deliveries … Finally, we do not know how to cure obesity. We try to help people, but when the disease is already well advanced, when there is a strong genetic and psychological component, a heavy history of eating disorders and diets, we cannot cure it.

PasseportSanté – Do you think that one day we will be able to cure it better? What types of treatments are you thinking of? Have you heard of a connected tablet capable of producing an artificial feeling of fullness?

The only very effective answer that we have found to the problem of obesity is bariatric surgery (a surgery which consists in restricting the absorption of food and therefore in limiting the caloric intake note), but it has many drawbacks. There is also a technique for external stimulation of the stomach which has been developed: electrodes are implanted which send the brain a virtual sensation of satiety, but it seems that this technique is not very well supported locally. As for the connected tablet, I have no opinion on it, I am wary of unique solutions to complex diseases. In fact, the ideal is not to gain weight so as not to lose it, take care of your weight immediately when you have gained some, and finally try not to gain weight when you have gained a lot. As a last resort, weight loss surgery can be a solution.

Health Passport – So, we talk a lot about obesity in your book, but what about the situation of people who, very occasionally, go on diet to lose 2 or 3 kilos?

As a doctor, we are biased, since by definition we only see people who have problems and cannot resolve them. It is quite likely that a number of people with a few extra pounds who do not really have a problem, whether genetic or psychological, are very successful in changing their eating habits and resolving their problems. weight problems.

PasseportSanté – With a view to weight loss, what does the role of a varied and balanced diet play for you?

Food always plays a role, but we must not think only in terms of the quantities swallowed, we must also think about the determinants of the patient’s eating behavior. By defending a varied and balanced diet, we do not necessarily get better results, but we at least try not to make people sick. Then you have to consider each person, and the problem is that not every obesity or every weight problem has an immediate and automatic dietary response, because not every weight problem is a food problem. We are looking for a global answer to people’s health problems, their behavioral problems, their psychological problems, their eating sensations. Finally, we review the objectives, we can not always guarantee a patient that he will lose weight by 15 kilos, so we try to impose the most acceptable constraints to be part of the long term, because the interest is not to lose weight in order to gain weight. Finally, 15 years later, the patients may not have lost weight, but at least they have not gained weight.

PasseportSanté – In the same way, how to explain that there are so many methods on the market (which moreover are qualified by their authors of “100% effective”)? In your opinion, are their authors aware of the dangers of their diets?

We have not succeeded in frankly showing that the regimes are dangerous, despite what the media may have said. On the other hand, we have succeeded in showing that diets are unbalanced, that they cause loss of muscle and bone, and that they make you gain weight. You could say that if patients had not dieted they would still have continued to gain weight, but diets certainly make the problem worse, and their authors are probably unaware of this, because most of the time they do not. not see patients who have failed. For their part, people who gain weight feel guilty and avoid talking about it. But every now and then there are successful patients. One of the attitudes that doctors can then have is to tell their patients that if they can’t do it, it’s their fault, since others have. Many specialists therefore do not hear, or do not want to hear, that what they do does not always work. This is to forget that obesity is a disease and that for a certain number of people, too overweight or too old, there is not much that can be done.

His detractors

Jean-Michel Lecerf

Head of the nutrition department at the Institut Pasteur de Lille, author of the book “To each his own true weight”.

“Not every weight problem is a food problem”

Read the interview

Helene Baribeau

Dietitian-nutritionist, author of the book “Eat better to be on top” published in 2014.

“You have to be in tune with your real needs”

Read the interview

Its defenders

Jean-Michel Cohen

Nutritionist, author of the book “I decided to lose weight” published in 2015.

“Doing regular diet sequences can be interesting”

Read the interview

Alain Delabos

Doctor, father of the concept of chrononutrition and author of numerous books.

“A diet that allows the body to manage its caloric potential on its own”

Read the interview