Daily associations between objective sleep and consumption of highly palatable food in free-living conditions.

Objectives: Prior studies have shown that individuals with shorter sleep duration and later sleep timing consume more highly palatable food (HPF). It is unclear if this relationship exists at the within-individual level, e.g. if sleeping less or later on one night is associated with greater HPF consumption in the following day in naturalistic environments. This study examined the daily associations between naturalistic sleep and HPF consumption.

Methods: Data were obtained from 78 healthy young adults (age = 20.38 [SD = 2.40] years). Participants carried a wrist actigraph and completed daily diaries tracking food consumption and covariates for seven consecutive days. Data were analysed using mixed models.

Results: Individuals with later bedtime were less likely to consume HPF at breakfast in the following day (odds ratio, OR [between] = 0.55 [0.44, 0.70], p  < 0.001). This association was also significant at the within-individual level (OR (within) = 0.85 [0.74, 0.97], p  = 0.016) - sleeping later on one night was associated with 15% decrease in the odds of consuming HPF at breakfast in the following day. Individual with later wake time had greater likelihood of consuming HPF at dinner (OR = 1.34 [1.03, 1.75], p  = 0.027).

Conclusions: Sleep schedules characterized by later bedtimes and later wake times were associated with lower HPF consumption earlier in the following day but greater HPF consumption later in the day. This pattern of energy intake might mediate the association between sleep and the risk of obesity.