Effects of Experimental Sleep Restriction on Energy Intake, Energy Expenditure, and Visceral Obesity

Abstract

Background: Although the consequences of sleep deficiency for obesity risk are increasingly apparent, experimental evidence is limited and there are no studies on body fat distribution.

Objectives: The purpose of this study was to investigate the effects of experimentally-induced sleep curtailment in the setting of free access to food on energy intake, energy expenditure, and regional body composition.

Methods: Twelve healthy, nonobese individuals (9 males, age range 19 to 39 years) completed a randomized, controlled, crossover, 21-day inpatient study comprising 4 days of acclimation, 14 days of experimental sleep restriction (4 hour sleep opportunity) or control sleep (9 hour sleep opportunity), and a 3-day recovery segment. Repeated measures of energy intake, energy expenditure, body weight, body composition, fat distribution and circulating biomarkers were acquired.

Results: With sleep restriction vs control, participants consumed more calories (P = 0.015), increasing protein (P = 0.050) and fat intake (P = 0.046). Energy expenditure was unchanged (all P > 0.16). Participants gained significantly more weight when exposed to experimental sleep restriction than during control sleep (P = 0.008). While changes in total body fat did not differ between conditions (P = 0.710), total abdominal fat increased only during sleep restriction (P = 0.011), with significant increases evident in both subcutaneous and visceral abdominal fat depots (P = 0.047 and P = 0.042, respectively).

Conclusions: Sleep restriction combined with ad libitum food promotes excess energy intake without varying energy expenditure. Weight gain and particularly central accumulation of fat indicate that sleep loss predisposes to abdominal visceral obesity. (Sleep Restriction and Obesity; NCT01580761).

Keywords: energy intake; obesity; sleep; sleep restriction; visceral fat; weight gain.

Figure 1.. Study outline.

Each 21-day study period consisted of 4 days/3 nights of acclimation (Days 1-4), then a 14-day/14-night experimental phase (Days 5-18), followed by a 3-day/3-night recovery (Days 19-21). Participants completed both sleep restriction and control sleep conditions in randomized order, after a >3-month wash-out. Gray bar indicates 9 hours of time in bed (from 22:00 to 7:00), while red bar indicates 4 hours of time in bed (from 00:30 to 4:30).

Figure 2.. Changes in energy intake and diet composition.

Adjusted mean changes from acclimation to experimental and recovery study phases in daily calorie (a), protein (b), fat (c), and carbohydrates (d) consumption across study days. Sleep restriction is presented in red and control sleep in gray. Error bars indicate SE.

Figure 3.. Changes in body weight and regional fat distribution.

Adjusted mean changes from acclimation to experimental and recovery study phases in body weight (a), total abdominal fat (b), subcutaneous fat (c), and visceral fat (d) areas across study days. Sleep restriction is presented in red and control sleep in gray. Error bars indicate SE. e. Representative abdominal computed tomography scans from a study participant during acclimation (Day 1) and experimental (Day 18) phases of control sleep (top left and top right, respectively), and of sleep restriction (bottom left and bottom right, respectively). Arrows indicate subcutaneous and visceral fat.

Central illustration.. Effects of experimental sleep restriction on obesity risk.

Twelve healthy individuals completed a randomized, controlled, crossover, 21-day inpatient study of sleep restriction (4-hour sleep opportunity) vs control sleep (9-hour sleep opportunity). During sleep restriction participants increased their daily energy intake by 308 Kcal compared to control sleep. Body weight increased in response to sleep restriction vs control sleep, with significant accumulation of abdominal visceral fat (~11%).