Effects of sleep restriction on food intake and appetite under free-living conditions: A randomized crossover trial

To investigate changes in subjective psychological factors and dietary intake during sleep restriction, we carried out a randomized crossover trial with a 3-day sleep restriction condition (SR; 5 h of sleep) and control sleep condition (CS; 8 h of sleep). Days 3 and 4 involved free-living and laboratory (in the morning) conditions, respectively. Subjective psychological factors (hunger, appetite, desire for sweets and fatty foods, sleepiness, and fatigue) were assessed using a 0.0–10.0 cm visual analog scale (VAS) every hour throughout the day on day 3, and at 8:00 a.m. on day 4. Dietary intake on day 3 was assessed on the basis of the food purchased and eaten. Fasting blood samples were collected at 8:00 a.m. on day 4. Dietary intake during the ad libitum breakfast was assessed on day 4. The participants were 13 women and 11 men (mean age, 21.4 ± 1.0 years; mean body mass index, 19.8 ± 1.7 kg/m²). The areas under the curve 0–16 h after waking for hunger, desire for fatty foods, sleepiness, and fatigue were higher in the SR than CS on day 3 (P < 0.05). Energy and carbohydrate intakes from snacks (daytime and nighttime) on day 3 were higher in the SR than CS (P < 0.05) but total dietary intake on day 3 was not different between the conditions (P > 0.05). The 2-arachidonoylglycerol level was different between the conditions (P < 0.05), but was not associated with sweet taste preference, dietary intake, or the active ghrelin level on day 4 (P > 0.05). In conclusion, ratings for subjective psychological factors and energy and carbohydrate intakes from snacks increased in association with sleep restriction under free-living conditions.