Penn Study: Changing Diet, for Better or Worse, Affects Sleep in a Big Way

A new Penn study shows dropping pounds could mean better shuteye.

Raise your hand if you are always tired. Like, so tired that you would not be surprised if you fell asleep at your desk right this second. Well, a new study performed by researchers at the University of Pennsylvania’s Perelman School of Medicine, published in the journal Sleep, found that changing your diet to lose a few pounds could impact more than just your waistline: For folks who are overweight, ditching a few pounds can lead to feeling more awake during the day, all while getting less (better quality) sleep at night. Three cheers for weight loss working double duty! The bad news: Small dietary changes in the wrong direction, even just for a little while, can have the opposite effect. Think: crappy sleep and lowered daytime energy.

According to a press release, the study was performed on mice who were given two different diets for eight weeks: the first group had a diet of regular chow and the second group was fed a high-fat diet. At the eight-week mark, some of the mice were given alternate diets for one week, plumping up the regular-chow mice, and causing the mice on the high-fat diet to lose weight, while some of the mice simply continued to consume their regular diet.

Here’s what they found:

“After the ninth week, mice maintained on HFD [high-fat diet] weighed 30 percent more, slept more than one hour longer per day, and suffered from increased wake fragmentation (frequently slipping into sleep) compared to mice maintained on RC [regular chow]. The “diet switch” groups, however, had similar body weight at week nine, but completely different sleep/wake profiles when compared to each other.”

Meaning? Well, according to the study’s researchers, the findings suggest that fluctuations in weight could affect your sleep patterns and the quality of sleep in a big way. The obese mice who switched to regular chow for just a week demonstrated the same sleep patterns as mice who’d been eating regular chow all along. And on the flip-side, those who switched to a crappy diet for just a week, packing on weight, had similar sleep patterns to the obese mice who’d been on the high-fat diet for all nine weeks — including an increased chance of falling asleep out of nowhere —  in just a week. Yikes. So long story short, for those who are overweight, dropping a few pounds can quickly lead to better sleep, and for those who are slim, packing on pounds fast can seriously screw with both your sleeping and waking hours.

While the study was done on mice and not humans, study co-author Sigrid Veasey, a professor in Sleep Medicine at Penn, says in the press release, “This study has mapped a completely novel food and sleep interaction. That changing to a healthier diet can acutely improve alertness and sleep, is extremely important and certainly an interaction to now test in humans.” Stay tuned.

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