Increased energy intake following sleep restriction in men and women: A one-size fits all conclusion?

OBJECTIVE: We assessed the degree of inter-individual responses in energy intake (EI) to an imposed sleep restriction versus habitual sleep duration protocol. We also investigated participant (age, sex, ethnicity and BMI) and study (study site, protocol order) characteristics as potential contributors to the variance in EI responses to sleep restriction between individuals. METHODS: Data from two randomized crossover trials were combined. All participants (n = 43; age: 31±7 years, BMI: 23±2 kg/m(2)) were free of medical/sleep conditions, non-smokers, reported not performing shift work, and having an average sleep duration of 7–9h/night. Ad libitum, 24h EI was objectively-assessed following sleep restriction (3.5–4h in bed/night) and habitual sleep (7–9h in bed/night) conditions. RESULTS: Large inter-individual variations in EI change (ΔEI) between restricted and habitual sleep conditions were noted (−813 to 1437 kcal/day). Only phase order was associated with ΔEI (β = −568 kcal/day, 95% CI for β = −921 to −215 kcal; P = 0.002); participants randomized to the habitual sleep condition first had greater increases in EI when sleep was restricted (P = 0.01). CONCLUSIONS: Large inter-individual variations in ΔEI following sleep restriction were noted, suggesting that not all individuals were negatively impacted by the effects of sleep restriction.