The Vicious Cycle of Food and Sleep

The future, my mother used to say, belongs to those who get up early. The future belongs to those who get up early. She said that as we drove to early skating practice on those cold winter mornings growing up in Quebec. As it turns out, science might agree with her — though perhaps not exactly in the way she thought.

I’m a researcher specializing in understanding the connections between diet, sleep and health. Up until about 2014, my lab focused on studying how lack of sleep affects obesity. Our work showed that reducing sleep by about four hours per night for four nights resulted in an increase in eating, which accounted for about 300 calories per day (the equivalent of a McDonald’s cheeseburger). We found that the cause is increased activity in the brain’s reward centers, which are specific to food, along with changes in the hormones that control satiety. In other words, people who sleep less feel hungrier and tend to crave foods high in sugar and fat.

Then, in 2014, the US Dietary Guidelines Advisory Committee — the group of scientists that makes recommendations about what Americans should eat to be healthy — turned to me to ask the opposite question: How does diet work looking for sleep? That was an exciting question.

It’s also a very important one. About 35 percent of Americans get less than the recommended minimum of seven hours of sleep a night; 10 to 30 percent suffer from a sleep disorder such as insomnia or sleep apnea. Insufficient sleep and sleep disorders are linked to a variety of problems ranging from mental illness to chronic diseases such as type 2 diabetes and cardiovascular disease.

But getting more and better sleep isn’t always just a matter of going to bed earlier: it turns out that diet is an underestimated factor in whether or not you sleep well.

Usually, people can trigger foods or beverages that contribute to poor sleep: drinking coffee too late in the day or eating a large meal too close to bed are two obvious causes that can interfere with sleep. What’s less noticeable is how healthy choices throughout the day can have a positive impact on sleep.

Our studies over the past seven years have shown that eating more fiber and less saturated fat and sugar during the day leads to deeper, less disrupted sleep at night. Eating a Mediterranean-style diet high in fruits and vegetables, legumes, nuts, whole grains, and olive oil, and low in red and processed meats and whole dairy, can be especially helpful. In our research, those who followed this diet were 1.4 times more likely to sleep well and 35 percent less likely to suffer from insomnia.

Why? One of the reasons for this is that protein-rich foods such as nuts and seeds, fish, poultry and eggs contain tryptophan, an amino acid from which the sleep-regulating hormone melatonin is formed in the brain. Other foods — including tomatoes, pineapples, tart cherries, bananas, apples, vegetable oils, nuts, and animal products — contain melatonin themselves. In plants, melatonin serves as an antioxidant to prevent damage, while in animals it serves to regulate their sleep (similar to humans). Eating such melatonin-rich foods may also increase your own melatonin levels, although research on this is sparse.

Our work suggests that the effects of diet on sleep can be as strong, or perhaps stronger, than mindfulness practices (increasing awareness and acceptance of one’s thoughts and feelings, such as through meditation) or melatonin supplementation through pills. Studies show that melatonin supplements reduce the time it takes to fall asleep by an average of four minutes; In one of our studies, a healthy diet reduced the time it took to fall asleep by about 12 minutes and improved sleep quality overall.

Ultimately, poor sleep and poor nutrition can be a vicious circle: lack of sleep leads to poor dietary choices, which in turn leads to poor sleep quality. But we can interrupt and reverse this cycle. Eating well throughout the day could lead to healthier, more restful sleep — which in turn could contribute to better food choices.

Interestingly, this may be easier to access for early risers. People who consider themselves night owls and feel most comfortable late in the day rather than early in the day tend to eat fewer plant-based proteins, fruits, and vegetables, on average. This evening preference is also associated (again, on average) with higher rates of illness and earlier death.

So maybe the future belongs to those who get up early after all.

Marie-Pierre St-Onge is a nutritionist and director of the Sleep Center of Excellence at Columbia University.


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