Overweight or obese adolescents ate more calories later in the evening, a new study found, according to Euronews.

The body’s internal clock may play a role in how much and when teenagers eat, new research suggests.

The study found that adolescents who were overweight or obese ate more calories later in the evening compared to those with a healthy weight.

“Going into this study, we knew that the circadian system affects hunger and metabolism,” Frank Scheer, a professor of medicine at Harvard Medical School in the United States and one of the study authors, said in a statement.

However, researchers wanted to see if this link persisted “when isolated from influences of environmental and behavioural cycles, including the light, sleep, and activity cycles”.

“This study is the first to demonstrate that food intake itself is regulated by our internal body clock,” Scheer added.

The researchers followed more than 50 teenagers aged between 12 and 18 who stayed in a controlled indoor environment with dimmed lighting when they were awake and complete darkness when they were asleep for 11 days and 10 nights.

The participants had a 28-hour schedule as part of the study instead of a traditional 24-hour sleep and wake cycle, the researchers said. Participants did not have clocks or natural light to influence their circadian clocks.

Researchers tracked when and how much they ate and found that teenagers’ eating habits were influenced by the body’s circadian system or biological clock, according to the findings published in the journal PNAS, with participants eating the most in the late afternoon and early evening and the least amount in the morning.

The teenagers who were overweight or obese ate more calories later in the day.

Physical and mental health benefits of a consistent schedule

“We do not fully understand the links between the behavioural and circadian cycles and eating, nor do we know the direction of the relationship,” David Barker, an associate professor of psychiatry and human behaviour at Brown University in the US and one of the study authors, told Euronews Health.

“There are many physical and mental health benefits to maintaining a consistent sleep schedule with age-appropriate sleep duration, and we encourage teens to work on improving their sleep,” he added in an email. Further research is needed to better understand the links between the body’s internal clock, food intake, and weight.

It could be that the differences among teens are not due to “how the circadian system operates per se” but potentially other factors such as “differences in hormones regulating hunger and satiety” or emotional or behavioural influences, according to Barker.

“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 behaviour,” Mary Carskadon, a professor of psychiatry at Brown University, added in a statement.

“The knowledge gained here opens a door to potential interventions that can enhance teen health moving forward,” she said.