Study finds teens with obesity consume more calories later in the day
A study found that teens with obesity eat more later in the day than their peers, highlighting the role of the body’s circadian system in eating habits.
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A new study from researchers at Mass General Brigham and the Warren Alpert Medical School of Brown University has found that teenagers with obesity tend to consume more calories later in the day than their peers with healthy weights.
The findings highlight the role of the body’s internal clock, or circadian system, in influencing eating habits. The study was published in the Proceedings of the National Academy of Sciences (PNAS).
“Going into this study, we knew that the circadian system affects hunger and metabolism. What remained unclear, however, was whether the circadian system—when isolated from influences of environmental and behavioral cycles, including the light, sleep, and activity cycles—directly influences food consumption,” said Frank A.J.L. Scheer, PhD, professor of Medicine and director of the Medical Chronobiology Program at Brigham and Women’s Hospital. “This study is the first to demonstrate that food intake itself is regulated by our internal body clock.”
The study examined 51 adolescents between the ages of 12 and 18 years, with an average age of 13.7 years. Participants were divided into 3 groups based on body mass index (BMI): 24 were classified as having a healthy weight, 13 as overweight, and 14 as having obesity.
To minimize external influences on circadian rhythms, the teens followed a controlled schedule in a dimly lit environment, with sleep and wake cycles lasting 28 hours and no access to natural light or clocks.
During the study, participants had 6 fixed meal opportunities per wake period and could eat as much as they wanted from a standardized menu. Researchers recorded the amount of food consumed and the time of day it was eaten.
The results showed that all groups ate more in the late afternoon and early evening, with calorie consumption being lowest in the morning. However, teens in the overweight and obesity groups consumed significantly more calories later in the day compared to those in the healthy weight group.
“The critical nature of adolescent development to set the stage for a lifetime of health highlights the need to understand the roles played by sleep/wake and circadian timing processes for eating behavior,” said Mary A. Carskadon, PhD, lead investigator of the study from the Warren Alpert Medical School. “The knowledge gained here opens a door to potential interventions that can enhance teen health moving forward.”
While the study establishes a link between circadian rhythms, eating habits, and weight, it does not determine whether altered eating patterns contribute to obesity or whether obesity affects circadian-driven eating behaviors. Future research will explore whether adjusting meal timing could influence weight management and overall health in adolescents.
Reference:
Bringham and Women's Hospital. Biological clock plays critical role in driving teens’ late eating habits. Eurekalert. February 17, 2025. Accessed February 17, 2025. https://www.eurekalert.org/news-releases/1073566?
