An estimated 15 million Americans work late-night and early-morning shifts, making the U.S. a largely sleep-deprived nation. This shift work has been so concerning that the World Health Organization has classified it as a “probable” cause of cancer. Neuroscientist Frank Scheer from Brigham and Women’s Hospital and Harvard Medical School studies sleep and circadian disorders and highlights the health risks associated with lack of sleep.
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Scheer states that insufficient sleep can increase the risk for various conditions, including cardiovascular disease, diabetes, and weight gain. He explains that the effects of sleep deprivation extend beyond overeating; sleep deprivation puts the body under stress.
In a recent study on the relationship between sleep and weight loss, participants restricted their calorie intake. However, those who slept less than five hours a night experienced a loss of lean muscle mass rather than fat. In contrast, participants who slept a full eight hours burned twice as much fat.
Previously, the link between sleep deprivation and weight gain was mainly attributed to increased hormone production that stimulates appetite. New findings suggest more complex physiological differences in how the body metabolizes food during sleep deprivation. Scheer notes that shift workers who consume calories at night do not process these calories as effectively.
He references a study conducted in the Netherlands, where one group had their sleep limited to four hours while the other group enjoyed a full night’s rest. The research revealed that the sleep-restricted group experienced a 21-percent decrease in insulin efficiency after just one night of sleep deprivation. This decreased efficiency could increase the risk of diabetes in the long term.
Scheer emphasizes that it is unnatural for the body to function and consume food during nighttime hours. While longitudinal studies have yet to directly link shift work and sleep deprivation to weight gain, emerging evidence suggests metabolic challenges are clear for those on overnight shifts. He advises shift workers to try to eat meals during regular daytime hours; however, this can be difficult for those working long overnight shifts. The reality for night workers often includes the dual challenges of exhaustion and metabolic stress.