To find out how sleep time affects diet during the day, researchers gathered 42 adults who admitted they don’t sleep much every night. Half of the participants stuck with their normal sleep schedule, while half were trained in sleep hygiene (like these 13 secrets from sleep doctors) with the goal of helping them sleep an extra 90 minutes every night. All the volunteers wore wrist monitors to track their sleep time, plus kept food diaries and tracked their physical activity and energy levels.
After four weeks, the group trained in good sleep habits added an average of 47 minutes between the time they fell asleep and woke up (26 minutes of which included nighttime wakefulness) compared to the group that didn’t change its schedule, according to the results in the American Journal of Clinical Nutrition. Plus, 86 percent started spending more time in bed, adding an extra 55 minutes on average. (If you’re tossing and turning, try these tips for sleeping better without drugs.)
That extra sleep showed some real-world benefits that could help explain why lack of sleep is associated with obesity. The sleep-trained group ate an average of 176 fewer calories a day; in comparison, the control group ate only seven fewer calories every day. Best of all, those calories were cut from less healthy sources. Those who slept more cut ten grams of sugar from their diets every day, while the others changed their sugar intake by less than a gram. The newly better sleepers reduced their daily carbs by 22 grams, while the shorter sleepers actually ate 3 more grams.
Even with better sleep and dietary habits, the participants didn’t show much weight change over the course of the study, but the results are consistent with past research linking sleep with a healthy weight, like one study that found people burn more fat when getting a full night’s rest. (Learn exactly how many hours of sleep you need to burn fat fast. ) The researchers are optimistic that a little extra shut-eye could be the boost people need when trying to shed pounds. “Our results … suggest that increasing time in bed for an hour or so longer may lead to healthier food choices,” lead study author and nutrition science researcher Haya Al Khatib, PhD, tells King’s College London.
If you’re ready to jump-start your better sleep plan, try these tiny changes that will help you sleep better in just one night.