I get a serious case of the munchies when I’m feeling sleep-deprived. A few short nights is all it takes to propel me to the places where the good stuff is. I break into the chocolate, corn chips, cheese, and salted nuts with the zeal of a wild pig rooting for truffles, and I eat and eat.
This reaction to feeling short on sleep is not uncommon, I discovered while conducting interviews for my book. Several insomnia sufferers talked of compensating for lack of energy by overeating and indulging in high-fat comfort foods. Pat, whose high-stress job as a lawyer routinely shortened his nights, felt there was a direct relationship between his insomnia and his weight.
“I’m someone who most of my adult life has been heavier than I want to be,” he said. “When you’re always tired, it’s easier to stress out and harder to be disciplined about eating and working out.”
What the Studies Say
Lots of evidence now links short sleep duration to weight gain and the development of metabolic syndrome (which leads to conditions such as heart disease and diabetes). Research affirms a relationship between sleep deprivation and overeating as well. A recent meta-analysis of the literature on lifestyle factors affecting the drive to eat found that alcohol consumption, sleep deprivation and TV watching significantly increased the short-term drive to eat.*
Another new study suggests that the hormonal factors involved in the increased drive to eat following short sleep may be different in men and women.** Researchers found that restricting subjects’ sleep to 4 hours a night for 3 nights led to
- increased levels of ghrelin in the men but not the women. Ghrelin is a hunger-stimulating hormone produced in the stomach and the pancreas.
- reduced levels of GLP-1 in the women but not the men. Produced in the intestine, GLP-1 is a satiety hormone whose levels increase with the eating of meals.
So the men’s response to sleep restriction was to have bigger appetites, and the women’s response was to feel less full. But whether you’re ravenous from the get-go or find it hard to stop eating once you’ve begun, the result is often weight gain and all its unwelcome consequences.
The obesity epidemic today gets blamed on dietary, socioeconomic, environmental, and genetic factors, and lack of exercise. I think more effort ought to go toward exploring the relationship between weight gain and short sleep.