Lack of sufficient sleep combined with free access to food increases calorie consumption and consequently fat accumulation, especially unhealthy fat inside the belly, According to new research from America’s Mayo Clinic.
Findings from a randomized controlled crossover study led by Ms. Naima Covassin, Ph.D., a cardiovascular medicine researcher at Mayo Clinic, show that lack of sufficient sleep led to a 9 percent increase in total abdominal fat area and an 11 percent increase in abdominal visceral fat, compared to control sleep. Visceral fat is deposited deep inside the abdomen around internal organs and is strongly linked to cardiac and metabolic diseases.
The findings are published in the Journal of the American College of Cardiology, and the study was funded by the National Heart, Lung and Blood Institute. Lack of sufficient sleep is often a behavior choice, and this choice has become increasingly pervasive.
More than one-third of adults in the U.S routinely do not get enough sleep, in part due to shift work, and smart devices and social networks being used during traditional sleep times. Also, people tend to eat more during longer waking hours without increasing physical activity.
“Our findings show that shortened sleep, even in young, healthy and relatively lean subjects, is associated with an increase in calorie intake, a very small increase in weight, and a significant increase in fat accumulation inside the belly,” said Mr. Virend Somers, M.D., Ph.D., the Alice Sheets Marriott Professor of Cardiovascular Medicine, and principal investigator of the study.
The study cohort consisted of 12 healthy people who were not obese, each spending two 21-day sessions in the inpatient setting. Participants were randomly assigned to the control (normal sleep) group or restricted sleep group during one session and the opposite during the next session, after a three-month washout period.
Each group had access to a free choice of food throughout the study. Researchers monitored and measured energy intake, energy expenditure, body weight, body composition, fat distribution, including visceral fat or fat inside the belly, and circulating appetite biomarkers.
The participants consumed more than 300 extra calories per day during sleep restriction, eating about 13 percent more protein and 17 percent more fat, compared to the acclimation stage. That increase in consumption was highest in the early days of sleep deprivation and then tapered off to starting levels during the recovery period. Energy expenditure stayed mostly the same throughout.
