Effects of Experimental Sleep Restriction on Weight Gain, Caloric Intake, and Meal Timing in Healthy Adults

Abstract

Study objectives: Examine sleep restriction's effects on weight gain, daily caloric intake, and meal timing.

Design: Repeated-measures experiments assessing body weight at admittance and discharge in all subjects (N = 225) and caloric intake and meal timing across days following 2 baseline nights, 5 sleep restriction nights and 2 recovery nights or across days following control condition nights in a subset of subjects (n = 37).

Setting: Controlled laboratory environment.

Participants: Two hundred twenty-five healthy adults aged 22-50 y (n = 198 sleep-restricted subjects; n = 31 with caloric intake data; n = 27 control subjects; n = 6 with caloric intake data).

Interventions: Approximately 8-to-1 randomization to an experimental condition (including five consecutive nights of 4 h time in bed [TIB]/night, 04:00-08:00) or to a control condition (all nights 10 h TIB/night, 22:00-08:00).

Measurements and results: Sleep-restricted subjects gained more weight (0.97 ± 1.4 kg) than control subjects (0.11 ± 1.9 kg; d = 0.51, P = 0.007). Among sleep-restricted subjects, African Americans gained more weight than Caucasians (d = 0.37, P = 0.003) and males gained more weight than females (d = 0.38, P = 0.004). Sleep-restricted subjects consumed extra calories (130.0 ± 43.0% of daily caloric requirement) during days with a delayed bedtime (04:00) compared with control subjects who did not consume extra calories (100.6 ± 11.4%; d = 0.94, P = 0.003) during corresponding days. In sleep-restricted subjects, increased daily caloric intake was due to more meals and the consumption of 552.9 ± 265.8 additional calories between 22:00-03:59. The percentage of calories derived from fat was greater during late-night hours (22:00-03:59, 33.0 ± 0.08%) compared to daytime (08:00-14:59, 28.2 ± 0.05%) and evening hours (15:00-21:59, 29.4 ± 0.06%; Ps < 0.05).

Conclusions: In the largest, most diverse healthy sample studied to date under controlled laboratory conditions, sleep restriction promoted weight gain. Chronically sleep-restricted adults with late bedtimes may be more susceptible to weight gain due to greater daily caloric intake and the consumption of calories during late-night hours.

Citation: Spaeth AM; Dinges DF; Goel N. Effects of experimental sleep restriction on weight gain, caloric intake, and meal timing in healthy adults. SLEEP 2013;36(7):981-990.

Keywords: Caloric intake; gender; late-night eating; macronutrients; meal timing; race; sleep restriction.

Figures

Figure 1

Effect of sleep loss on weight gain. (A) Subjects were healthy adults aged 22-50 y with a body mass index ranging between 19-30. Sleep-restricted subjects gained significantly more weight than control subjects (d = 0.51). (B) Among sleep-restricted subjects, African Americans gained more weight than Caucasians (d = 0.37) and males gained more weight than females (d = 0.38). Data expressed as mean ± standard error of the mean, *P < 0.05.

Figure 2

Caloric intake by day of protocol. (A) Sleep-restricted subjects consumed significantly more calories during days when bedtime was delayed to 04:00 (EW-SR4) compared to days when bedtime was 22:00 (BL, R1-2). Caloric intake did not differ between BL and SR5 (when waking hours were equivalent and bedtime was 22:00). Caloric intake did not differ between BL and each recovery day (R1-2). (B) Sleep-restricted subjects and control subjects did not differ in caloric intake during days when both groups had a 22:00 bedtime (BL, SR5, R1-2). Sleep-restricted subjects consumed more calories than control subjects during days when they had a 04:00 delayed bedtime (EW, SR1-4; d = 0.94). Data expressed as mean ± standard error of the mean. BL, baseline; EW, extended wakefulness; R, recovery; SR, sleep restriction.

Figure 3

Effect of sleep loss on meal timing. (A) Subjects consumed significantly fewer calories from 08:00-14:59 on days following sleep restriction (SR1-5) compared to days following baseline sleep (BL and EW). During days with a delayed bedtime (EW, SR1-4), subjects consumed on average of 552.9 calories from 22:00-03:59. (B) The amount of calories derived from protein was significantly greater during 15:00-21:59 and was significantly reduced during 22:00-03:59 compared to the other two time intervals. Compared to the other two time intervals, the amount of calories derived from carbohydrates was significantly greater during 08:00-14:59 and the amount of calories derived from fat was significantly greater during 22:00-03:59. See text for explanation of time intervals. Data expressed as mean ± standard error of the mean, *P < 0.05. BL, baseline; EW, extended wakefulness; SR, sleep restriction.