Late eating favors obesity?
The management of food intake and feelings of hunger and satiety is under the control of hormones secreted in the brain in a circadian manner, i.e. with a period approximately equal to 24 hours. Hunger and satiety are sensations respectively due to the production of ghrelin and leptin. Ghrelin triggers the metabolism of lipid storage, whereas leptin has the opposite effect, i.e. their degradation.
The link between late meals and obesity is known, but the underlying mechanism was still a mystery. Is it due to changes in hunger and appetite sensations? Energy expenditure? Or both? Is the adipose tissue, the place where lipids are stored, involved? A study published at the beginning of October 2022 answered these questions by comparing overweight or obese individuals who ate early and others who ate late (4 hours apart), while strictly controlling the rest of the parameters (caloric balance, physical activity, sleep time, etc). Their conclusions were that eating late increases the feeling of hunger (imbalance of the ghrelin/leptin ratio), decreases energy expenditure, internal body temperature and increases fat storage. As you may have guessed, all of these elements promote weight gain.
Obesity (BMI ≥ 30) is a public health problem that affects 650 million people worldwide and causes many comorbidities. Nevertheless, it is a chronic disease that remains reversible until it is installed. Research to understand the mechanisms that lead to obesity is therefore of major importance to prevent its development.