A new study provides evidence that eating late at night reduces energy expenditure, increases hunger and increases fat tissue, which together may increase the risk of obesity. The latter could be a source of serious diseases.

As attractive as a fridge full of goodies is in the evening, it’s not advisable to snack too late, nutritionists have been saying for some time. A study by US scientists now provides concrete evidence of the harm midnight snacking can do to the body.

Obesity afflicts approximately 42 percent of the U.S. adult population and contributes to the onset of chronic diseases, including diabetes, cancer, and other conditions.

Brigham and Women’s Hospital research group examined 16 patients with a body mass index (BMI) in the overweight or obese range. Each participant completed two laboratory protocols: one with a strictly scheduled early meal schedule, and the other with the exact same meals, each scheduled about four hours later in the day.

In the last two to three weeks before starting each of the in-laboratory protocols, participants maintained fixed sleep and wake schedules, and in the final three days before entering the laboratory, they strictly followed identical diets and meal schedules at home.

In the lab, participants regularly documented their hunger and appetite, provided frequent small blood samples throughout the day, and had their body temperature and energy expenditure measured.

Eating late in the day has been shown to increase waking hunger and reduce serum levels of the hormone leptin, which regulates hunger. In addition, late eating reduces waking energy expenditure and body temperature; fat storage is increased. All these may contribute to the incidence of obesity.

According to the authors, the results are not only consistent with a number of studies that suggest that eating later in life may increase the likelihood of developing obesity, but also reveal the cause of this phenomenon.

Through cross-sectional analysis and rigorous control of behavioral and environmental factors such as physical activity, posture, sleep and light exposure, the researchers were able to detect changes in the various control systems involved in energy balance.

In future studies, the research group aims to recruit more women so that their results can be more widely interpreted. For example, their goal is to investigate the effect of the relationship between mealtime and bedtime on energy balance.

Source: Brigham and Women’s Hospital