Weight loss due to diet changes can improve sleep at any weight, says a study published by researchers from the University of Pennsylvania.
The findings offer new insights into how weight fluctuations impact numerous aspects of sleep independent of body weight.
Previous studies have linked obesity with persistent sleepiness, lack of energy during the day, and poor sleep quality, all of which can be successfully combatted with weight loss treatment.
But until now, researchers have known little about the link between excessive weight, poor dietary habits, and sleep/wake abnormalities.
Nearly 185 million adults and 24 million children in the United States are overweight or obese. In Philadelphia, an estimated 68 percent of adults are overweight or obese.
Beyond impaired cognitive function, poor sleep is associated with a host of chronic health problems including depression, obesity, and hypertension.
Additionally, the Centers for Disease Control and Prevention estimates that 50 to 70 million U.S. adults experience sleep or wakefulness disorders.
In the current research, obesity was studied using diet-induced obese mice.
Half the mice were randomly chosen to receive regular chow (RC) while the other mice were fed a high-fat diet (HFD, more than three times higher in fat content) for eight weeks.
At the end of that period, some of the mice were switched to the alternative diet for one week, causing newly-fed HFD mice to gain weight and newly-fed RC mice to lose weight, while the rest of the mice continued to consume their current diet.
After the ninth week, mice maintained on HFD weighed 30% 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.
The “diet switch” groups, however, had similar body weight at week nine, but completely different sleep/wake profiles when compared to each other.
“Our findings suggest body weight is a less important factor than changes in weight for regulating sleepiness,” said the study’s lead author.
“Diet-induced obese mice that ate a regular chow diet for only one week showed the same sleep/wake profile as mice that ate a regular chow diet for nine weeks.”
The findings have implications for the lean population as well, since mice consuming the low-fat diet for eight weeks followed by only one week of HFD had similar sleep as those eating a HFD for nine weeks.
As individuals pursue these dietary changes, they may start to feel more awake during the day and be motivated to live a healthier lifestyle.
Citation: Perron IJ, et al. (2015). Diet/energy balance affect sleep and wakefulness independent of body weight. SLEEP, 38: 1893–1903. DOI: http://dx.doi.org/10.5665/sleep.5236.
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