A new study reveals that eating a meal late at night increases several factors contributing to overweight and obesity.
- According to this study, eating dinner four hours later, for example at 10 p.m. instead of 6 p.m., reduces satiety, the amount of calories burned and causes changes in fatty tissue, which can contribute to overweight.
- Nearly one in two French people (47.3%) is overweight or obese, according to figures from the League Against Obesity in 2020. 17% of adults are obese, i.e. nearly 8.6 million people.
Health professionals have been warning about the dangers of nighttime snacking for years. A new studypublished in Cell Metabolism, brings them new arguments. Brigham and Women’s Hospital researchers say eating a meal at 10 p.m. instead of 6 p.m. reduces calorie burning, increases hunger and causes chemical changes in fatty tissue, which may contribute to weight gain . Eating late would therefore cause significant changes in our level of hunger, the way we burn calories after eating and the way we store fat.
Less satiety, calories burned and more fat stored for late eaters
“We wanted to test the mechanisms that may explain why eating late increases the risk of obesity,” explains the lead author, Professor Frank AJL Scheer, in a communicated. “Previous research by us and others has shown that eating late is associated with an increased risk of obesity, increased body fat and reduced weight loss. We wanted to understand why,” he adds. Previous experiments had shown that meals just before bedtime had profound effects on the appetite-regulating hormones leptin and ghrelin.
Levels of the hormone leptin, which signals satiety, were lower over the next 24 hours in those who ate late compared to those who ate earlier. When participants ate later, they also burned calories at a slower rate and stored more fat.
Overweight: how was this study on the impact of late dining carried out?
To achieve these results, the research team recruited 16 participants with a body mass index (BMI) corresponding to overweight or obesity. Among them, one group had an early dinner, at 6 p.m., and the other four hours later. They regularly documented their hunger and appetite and provided small blood samples frequently, while having their body temperature and energy expenditure measured. The researchers also collected adipose tissue biopsies to analyze how the dinner schedule affected adipogenesis (the way the body stores fat).
“This study shows the impact of late eating compared to early eating. Here, we isolated these effects by controlling for confounding variables such as calorie intake, physical activity, sleep, and exposure to light, but in real life many of these factors can themselves be influenced by meal times”explains Scheer.
In their next studies, Professor Scheer and his team aim to recruit more women. The study group included only five participants, so that the menstrual phase would not interfere with the results. In the future, they also want to better study the effects of mealtime and bedtime on energy balance.