You know that when you sleep poorly, it’s easy to overindulge in junky snacks the next day. It’s one of the reasons why problems sleeping are associated with an increased risk for obesity.

But the opposite is true too—eating poorly can interfere with the quality of your sleep.

Researchers have long suspected this, but now they have shown that it happens—and what nutrients are the worst culprits.

Researchers at Columbia University College of Physicians and Surgeons studied 26 normal-weight men and women in their 30s and 40s. None had insomnia or other sleep problems. For one part of the study, participants ate a balanced, healthy diet provided by the researchers. For the next part, they were given an allowance to buy their own food, which the researchers then weighed before and after consumption so that they knew what and how much the participants ate.

Results: Diet didn’t affect how long participants slept—the average was about seven-and-a-half hours—but it had a big effect on how well they slept. Those who ate the most fiber-rich foods (think fruits and vegetables) fell asleep more quickly and spent more time in the truly refreshing deepest stage of sleep. Conversely, those who ate the most high-sugar, high-saturated-fat foods (think cookies and ice cream) spent less time in that oh-so-healthy deep sleep. Refined carbs, such white bread and white rice, also were linked with poorer sleep.

Sounds like a vicious cycle? Right you are! Sleep poorly because you ate poorly…then eat poorly because you slept poorly…then sleep poorly again…and so on. This may describe you or someone you know right now.

The solution to this vicious cycle, according to study author Marie-Pierre St-Onge, PhD, is to start by practicing the best sleep habits you can at night and then use the benefits of a good night’s sleep to eat better the next day. You probably already know what to do—a really dark room, a comfortably cool room temperature and no electronics use right before bedtime.

The better the quality of your sleep—what sleep researchers call the architecture of sleep—the easier it should be to make smart, healthy food choices the next day.

If you do eat right, the result should be better sleep quality that next night.

Which then makes it easier to eat right the next day…

To learn more, see Bottom Line’s Guide to Better Sleep…No Sleeping Pills Needed.