How Circadian Misalignment Affects Weight Gain
A Circadian rhythm is the cycle our bodies attune to day after day over a 24 hour period. Depending on what type of work schedule or other events going on in ones life, the Circadian rhythm can vary widely from person to person. The key to maintaining that rhythm is consistency in any schedule. Whether someone works during the day and sleeps during the night, or vice versa, the body will attune itself to that schedule over time. If someone is on an alternating schedule, shifting from workings days to nights often, or changing time zones often, or simply is not consistent with when they sleep, eat, and exercise, that rhythm is thrown off.
Zitting et al. investigated how Circadian rhythm affects energy expenditure and weight loss. It is known from previous studies that Circadian misalignment increases the risk of obesity. However it is not clear whether the increased weight gain is due to increased caloric intake or decreased energy expenditure. One finding is that sleep deprivation in general caused a decrease in energy expenditure, contributing to weight gain. Changes in resting energy expenditure, or the energy the body expends just to perform internal bodily functions, was indicated as a possible mechanism for decreased total energy expenditure. Behavior changes due to an irregular schedule may also contribute to decreased activity and increased caloric intake leading to weight gain.
Although some people are forced into irregular schedules due to work obligations, a typical contributor to Circadian misalignment is socially driven. Staying up or sleeping in extremely late on weekends can influence the rhythm. For athletes, creating a consistent schedule including sleep, meals, and workouts will help to maintain the Circadian rhythm and ensure that unnecessary weight gain is not caused, in addition to other unwanted hormonal and behavior changes.
You can find the article here: https://www.cell.com/current-biology/pdfExtended/S0960-9822(18)31334-4