Late dinner may cause obesity

Having dinner much later in the night promotes nocturnal glucose intolerance and reduces fatty acid oxidation and mobilization, especially in those who sleep early, suggests a study, adding that such effects may lead to obesity if they recur chronically.

“Consuming calories later in the day is associated with obesity and metabolic syndrome,” the investigators said.

Twenty healthy volunteers (mean age, 26.0 years; body mass index, 23.2 kg/m²; 10 female) accustomed to a bedtime between 22:00 and 01:00 were enrolled in this randomized crossover trial of late dinner (LD, 22:00) vs routine dinner (RD, 18:00), with a fixed sleep period (23:00–07:00) in a laboratory setting.

An isocaloric macronutrient diet was administered on each visit. The investigators provided dinner (35-percent daily kcal, 50-percent carbohydrate, 35-percent fat) with an oral lipid tracer ([²H₃₁] palmitate, 15 mg/kg) at 18:00 with RD and 22:00 with LD.

Nocturnal and next-morning hourly plasma glucose, insulin, triglycerides, free fatty acids (FFAs), cortisol, dietary fatty acid oxidation, and overnight polysomnography were then measured.

LD resulted in a 4-hour shift in the postprandial period, which overlapped with the sleep phase. The postprandial period following LD was associated with higher glucose, a triglyceride peak delay, and lower FFA and dietary fatty acid oxidation independent of the 4-hour shift. Additionally, LD demonstrated no effect on sleep architecture, but it led to an increase in plasma cortisol.

“These metabolic changes were most pronounced in habitual earlier sleepers determined by actigraphy monitoring,” according to the investigators.