SAN ANTONIO – In adults of normal weight, a small controlled study has shown that a , independent of caloric intake.
Doug Brunk/MDedge News
Dr. Namni Goel
The findings come from an 8-week controlled trial presented at the annual meeting of the Associated Professional Sleep Societies, which set out to examine the impact of a daytime versus delayed eating schedule on body mass, adiposity, and energy homeostasis in adults of normal weight.
“It is best to stop eating as early as possible in the day, and to not eat late at night,” the study’s first author, Namni Goel, PhD, said in an interview at the meeting. “There’s an open question in our field: Should you stop eating at 7:00 p.m.? 8:00 p.m.? My own feeling is, the longer it is between when you stop eating and go to bed, the better off you are metabolically.”
Dr. Goel, associate professor in the division of sleep and chronobiology in the department of psychiatry at the University of Pennsylvania, Philadelphia, and colleagues enrolled 12 healthy adults to participate in a randomized cross-over study in free-living conditions. Three meals and two snacks consisting of comparable energy and macronutrient content were provided during two 8-week counterbalanced phases: 1) daytime eating (food consumed between 8:00 a.m. and 7:00 p.m, and 2) delayed eating (food consumed between 12:00 p.m. and 11:00 p.m. A 2-week washout period occurred between the conditions. “What we wanted to do is just manipulate the timing of eating and we provided all of the meals so we could control the caloric intake,” Dr. Goel said.
The researchers asked participants to maintain a sleep-wake cycle between 11:00 p.m. and 9:00 a.m. (verified by wrist actigraphy) and to limit physical activity. They assessed weight, adiposity, energy metabolism, and hormonal markers during four inpatient visits: 1) baseline; 2) after the first eating condition; 3) after the washout period, before the second eating condition began; and 4) after the second eating condition. They used two-way analysis of variance and Cohen’s d effect sizes to examine changes in anthropometrics and metabolic measures affected by eating schedule (daytime vs. delayed) and time (before vs. after each eating schedule).