Dietary intake following experimentally restricted sleep in adolescents

Abstract

Study objective: To examine the relationship between sleep and dietary intake in adolescents using an experimental sleep restriction protocol.

Design: Randomized crossover sleep restriction-extension paradigm.

Setting: Sleep obtained and monitored at home, diet measured during an office visit.

Participants: Forty-one typically developing adolescents age 14-16 years.

Interventions: The 3-week protocol consisting of a baseline week designed to stabilize the circadian rhythm, followed randomly by 5 consecutive nights of sleep restriction (6.5 hours in bed Monday-Friday) versus healthy sleep duration (10 hours in bed), a 2-night washout period, and a 5-night crossover period.

Measurements: Sleep was monitored via actigraphy and teens completed validated 24-hour diet recall interviews following each experimental condition.

Results: Paired-sample t-tests examined differences between conditions for consumption of key macronutrients and choices from dietary categories. Compared with the healthy sleep condition, sleep-restricted adolescents' diets were characterized by higher glycemic index and glycemic load and a trend toward more calories and carbohydrates, with no differences in fat or protein consumption. Exploratory analyses revealed the consumption of significantly more desserts and sweets during sleep restriction than healthy sleep.

Conclusions: Chronic sleep restriction during adolescence appears to cause increased consumption of foods with a high glycemic index, particularly desserts/sweets. The chronic sleep restriction common in adolescence may cause changes in dietary behaviors that increase risk of obesity and associated morbidity.

Keywords: Adolescence; glycemic index; glycemic load; obesity; pediatrics; sleep deprivation.

Figure 1

Schematic diagram of the sleep protocol. Teens were asked to maintain a constant wake time across all 3 weeks. They were allowed to self-select their bedtimes during the baseline week, as well as the Saturday and Sunday nights between conditions. On Monday-Friday nights during the experimental week, their bedtimes were modified to cause sleep restriction (sleep restriction; 6.5 h in bed per night) or allow healthy sleep duration (healthy sleep condition; 10 h in bed per night with lights out). Dietary assessments were conducted on the Saturday morning at the end of each experimental week, asking about intake throughout the previous day (Friday).

Figure 2

Average sleep patterns, as estimated by actigraphy, for the baseline condition, the weekends that preceded each experimental condition, and each experimental condition (SR, sleep restriction; HS, healthy sleep condition). Mean sleep onset time is marked by the bottom of each bar, and sleep offset by the top of each bar. Mean sleep duration is printed within each bar. The baseline and weekend sleep durations did not significantly differ (P > 0.05) but collectively were significantly shorter than the HS condition (P < 0.001) and longer than the SR condition (P = 0.001). The adolescents averaged 2.53 h (SD = 0.68) more sleep during the HS condition than the SR condition (P < 0.001) due to changes in sleep onset (P < 0.001) without differences in wake times (P = 0.561).