Circadian rhythms and meal timing: impact on energy balance and body weight

Abstract

Energy metabolism and appetite regulating hormones follow circadian rhythms which, when disrupted, could lead to adverse metabolic consequences. Such circadian misalignment, a mismatch between endogenous circadian rhythms and behavior, is most severely experienced by shift workers, due to nighttime wake, daytime sleep, and eating at night. However, circadian misalignment is not restricted to shift workers; milder shifts in sleep and mealtimes, termed social and eating jetlag, are highly prevalent in the general population. Social and eating jetlag result in later mealtimes, which may promote positive energy balance and weight gain. Earlier meal timing, specific to individual endogenous circadian patterns, could serve to reduce cardiometabolic disease burden and aid in weight loss and interventions should be done to test this.

Figure 1.

An overview of how mistimed sleeping and eating result in circadian misalignment and the metabolic consequences. (a) The circadian system promotes wakefulness/feeding during the biological day and sleep/fasting during the biological night. (b) Several behavioral patterns do not fit these endogenous preferences. Shift work: Awake/feeding at night and sleeping/fasting during the day, causing severe circadian misalignment. Social Jetlag: A shift in the midpoint of sleep on workdays vs. free days, causing mild circadian misalignment. Eating jetlag: A shift in the midpoint of the feeding episode on workdays vs. free days, causing mild circadian misalignment. These behavioral patterns result in a mismatch between the timing of eating/sleeping and the endogenous circadian system (indicated in magenta). Circadian misalignment is thought to disrupt energy balance, resulting in increased body weight and cardiometabolic risk.