“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,” lead investigator Mary Carskadon, a professor of psychiatry and human behavior at Brown University and director of the Bradley Hospital Sleep Research Laboratory, said in a statement. “The knowledge gained here opens a door to potential interventions that can enhance teen health moving forward.”
While experts have known the circadian system influences metabolism and hunger, there has been little known about whether it “directly influences food consumption,” Brown said in a press release.
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“This study is the first to demonstrate that food intake itself is regulated by our internal body clock,” study author Frank Scheer, director of the Medical Chronobiology Program at Brigham and Women’s Hospital, said in a statement.
According to university officials, the study was conducted at the Bradley Hospital Sleep Research Laboratory. Participants were divided into three groups based on body mass index and placed on 28-hour sleep and wake cycles for 11 days and 10 nights “and stayed in controlled dim-light settings while awake and in complete darkness during sleep,” the release states.
“To control for outside influences on circadian rhythm, researchers removed all external time cues from the lab’s environment, including clocks and access to natural light,” the university said.
Participants were given six opportunities to eat at fixed times and could consume as much food as they wanted, according to researchers.
“The results showed that changes in the circadian system throughout the day and night significantly influenced food consumption. In all three groups, food intake peaked in the late afternoon and early evening and was lowest in the morning, even after accounting for behavioral and environmental factors, demonstrating that the body’s biological clock directly impacts how much people eat at different times of the day,” Brown said in the release.
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“Adolescents in the obesity and overweight groups consumed significantly more calories in the circadian evening compared to those in the healthy weight group. Researchers found no significant differences in total sleep time between or within the groups across sleep cycles.”
According to researchers, additional studies are needed to learn whether “affecting circadian control of food intake contributes to weight changes, if weight changes impact the circadian control of food intake, or a combination of the two.”
Findings from the study could help clinicians with how to counsel adolescents about weight management, Carskadon said.
“For example, the influence of circadian timing could be influenced by excluding light late in the day and enhancing bright light in the morning, especially while exercising,” Carskadon said. “That might help pull the rhythms to a better place — and also create healthy habits.”
Christopher Gavin can be reached at christopher.gavin@globe.com.