Une étude de Stanford révèle les secrets d’une perte de poids durable : comportements et biomarqueurs exposés

Concept de perte de poids obésité

Les chercheurs de Stanford Medicine ont découvert des biomarqueurs qui peuvent prédire la capacité d’un individu à perdre du poids et à maintenir sa perte de poids à long terme. Ces biomarqueurs comprennent des signatures du microbiome intestinal, des protéines fabriquées par le corps humain et des niveaux de dioxyde de carbone expiré. L’étude a révélé que les bactéries présentes dans l’intestin et les quantités de certaines protéines produites par le corps peuvent avoir un impact sur la capacité d’un individu à maintenir une perte de poids. De plus, la recherche a révélé que certaines personnes perdent plus de poids avec des régimes faibles en gras tandis que d’autres ont de meilleurs résultats avec des régimes faibles en glucides.

Une nouvelle analyse des données d’une étude d’un an sur la perte de poids a identifié les comportements et les biomarqueurs qui contribuent à la perte de poids à court et à long terme.

Suivre strictement un régime – soit sain à faible teneur en glucides, soit sain à faible teneur en matières grasses – était ce qui importait pour la perte de poids à court terme au cours des six premiers mois. Mais les personnes qui ont maintenu une perte de poids à long terme pendant un an ont mangé le même nombre de calories que celles qui ont repris du poids ou qui n’ont pas perdu de poids au cours des six mois suivants.

Alors qu’est-ce qui explique cette différence ?

Selon l’étude, les bactéries vivant dans votre intestin et les quantités de certaines protéines que votre corps fabrique peuvent affecter votre capacité à maintenir une perte de poids. Et il s’avère que certaines personnes perdent plus de poids avec des régimes faibles en gras, tandis que d’autres réussissent mieux avec des régimes faibles en glucides.

Les chercheurs de Stanford Medicine ont identifié plusieurs biomarqueurs qui prédisent dans quelle mesure un individu réussira à perdre du poids et à le maintenir à long terme. Ces biomarqueurs comprennent des signatures du microbiome intestinal, des protéines fabriquées par le corps humain et des niveaux de dioxyde de carbone expiré. Les chercheurs ont publié leurs découvertes le 13 décembre dans la revue

“Weight loss is enigmatic and complicated, but we can predict from the outset with microbiome and metabolic biomarkers who will lose the most weight and who will keep it off,” said Michael Snyder, PhD, professor and chair of genetics and co-senior author on the paper.

Willpower does not drive weight loss

The data came from 609 participants who logged everything they ate for a year while following either a low-fat or low-carb diet made up of mostly high-quality, minimally processed foods. The researchers tracked participant exercise, how well they followed their diet, and the number of calories consumed.

The study showed that just cutting calories or exercising were not enough to sustain weight loss over a year. To try and understand why, the team turned their focus to biomarkers of metabolism.

“We found specific microbiome ecologies and amounts of proteins and enzymes at the beginning of the study period — before people started following the diet — that indicated whether they would be successful at losing weight and keeping it off,” said Dalia Perelman, research dietician and co-lead author on the paper.

Throughout the study, the researchers measured the ratio of inhaled oxygen to exhaled carbon dioxide, known as a respiratory quotient, which serves as a proxy for whether carbohydrates or fats are the body’s primary fuel. A lower ratio means the body burns more fat, while a higher ratio means it burns more carbohydrates. So, those who started the diet with a higher respiratory quotient lost more weight on a low-carb diet.

“There are people who can be eating very few calories but still sustain their weight because of how their bodies metabolize fuels. It is not for lack of will: It is just how their bodies work,” Perelman said.

In other words, if your body prefers carbs and you’re predominately eating fat, it will be much harder to metabolize and burn off those calories.

“If you are following a diet that worked for someone you know and it is not working for you, it might be that that specific diet is not as suited for you,” added Xiao Li, PhD, co-lead author of the paper, a former postdoctoral fellow at Stanford Medicine who is now at Case Western University.

For now, focus on nutrients

The predictive information gleaned from the gut microbiome, proteomic analysis, and respiratory quotient signatures is laying the foundation for personalized diets. Snyder said he thinks tracking amounts of certain gut microbe strains will be a way for people to determine which diets are best for weight loss.

We’re not there yet, so until then, according to the researchers, the focus should be on eating high-quality foods that are unprocessed and low in refined flours and sugar.

The research team identified specific nutrients that were correlated with weight loss during the first six months. Low-carb diets should be based on monounsaturated fats — such as those that come from avocados, rather than bacon — and high in vitamins K, C, and E. These vitamins are in vegetables, nuts, olives, and avocados. Low-fat diets should be high in fiber, such as is found in whole grains and beans, and avoid added sugars.

“Your mindset should be on what you can include in your diet instead of what you should exclude,” Perelman said. “Figure out how to eat more fiber, whether it is from beans, whole grains, nuts, or vegetables, instead of thinking you shouldn’t eat ice cream. Learn to cook and rely less on processed foods. If you pay attention to the quality of food in your diet, then you can forget about counting calories.”

Reference: “Distinct factors associated with short-term and long-term weight loss induced by low-fat or low-carbohydrate diet intervention” by Xiao Li, Dalia Perelman, Ariel K. Leong, Gabriela Fragiadakis, Christopher D. Gardner and Michael P. Snyder, 13 December 2022, Cell Reports Medicine.
DOI: 10.1016/j.xcrm.2022.100870

Christopher Gardner, professor of medicine and co-senior author on the paper, also contributed to this work.

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