Moderation and variety are two important keys to eating well for health. Eating a wide range of foods in moderate amounts are hallmarks of a diet in balance, and great ways to help achieve and maintain a healthy weight. Sleep is also an important component of overall health and weight regulation. How do sleep and diet work together? That's the subject of a new study, which indicates that people who sleep less than seven to eight hours a night may consume more daily calories and eat a less varied diet.
Researchers at the Perelman School of Medicine at the University of Pennsylvania examined the dietary differences among people with different sleep patterns, and found that people who reported sleeping the recommended seven to eight hours per night consumed fewer calories than those who reported sleeping five to six hours per night. People who slept between seven and eight hours nightly also had more diverse diets than those who slept both less and more than this recommended nightly amount. Eating a wide range of foods is considered an indicator of a healthy diet.
Researchers used data from the National Health and Nutrition Survey (NHANES), a population-based survey of the health and nutrition habits of adults and children in the U.S., conducted annually by the Centers for Disease Control. As part of the survey, participants report their nightly sleep amounts. Researchers used this information to create four sleep categories:
Very short sleep: Those who slept fewer than five hours per night
Short sleep: People who slept five to six hours nightly
Standard sleep: Those who slept seven to eight hours per night
Long sleep: People who slept for nine or more hours nightly
The NHANES data also included detailed information about participants' daily eating habits. Using this information, researchers analyzed how the diets of short and long sleepers differed from standard sleepers, in terms of the range of foods and nutrients, and also calorie intake. They found that calorie consumption differed among the four groups:
- Short sleepers, those who slept between five and six hours nightly, consumed more calories than any other group.
- Short sleepers were followed by standard sleepers, very short sleepers, and long sleepers, in the overall amount of calories consumed daily.
Researchers also found differences in the makeup and quality of diets across the four groups:
- Standard sleepers, those who slept seven to eight hours, had the most broadly varied diet of all the groups.
- Very short sleep was associated with lower consumption of tap water, as well as carbohydrates and lycopene, a nutrient found in red and orange vegetables such as tomatoes. Lycopene is an antioxidant, and may protect against cancer and heart disease.
- Short sleep was associated with lower amounts of Vitamin C, tap water and selenium, a mineral found in fish, meat, and nuts. Selenium helps to protect heart health, and may reduce the risk of some cancers.
- Long sleep was linked to lower carbohydrate consumption, as well as lesser amounts of theobromine. Theobromine is a stimulant, similar to caffeine but much weaker, which is found in chocolate and tea. Theobromide also has relaxing effects, and may help to lower blood pressure. Long sleep was also associated with greater alcohol consumption.
We don't know from this study whether diet is influencing sleep or sleep is influencing food choice, or both. But the evidence is abundant that these two pillars of health -- sleep and diet -- affect each other in a number of ways. We've seen a great deal of research that diet and weight control are strongly influenced by sleep, and that too little sleep can make eating healthfully more challenging:
- Sleep deprivation disrupts hormones that regulate appetite, according to a number of recent studies. Being low on sleep increases feelings of hunger, a result of imbalances to the levels of hormones ghrelin and leptin, which work to regulate appetite.
- Being short on sleep can also compromise our ability to select healthy foods. Changes to brain chemistry brought about by insufficient sleep affect impulse control and judgment, resulting in poor food choices. And short sleep has also been shown to activate the reward centers of the brain, making junk food appear even more enticing.
- Other research has also shown that too little sleep is linked to increased calorie intake and to eating more high-fat foods. This study found that men who were sleep deprived consumed an average of an additional 263 calories daily, compared to men who got sufficient sleep. Women who were sleep deprived consumed an average 329 extra calories daily. Both men and women also ate greater proportions of high-fat and high-protein foods. And this study concluded that people short on sleep were more likely to consume more of their overall calories from snacks, with higher carbohydrate amounts.
Sleep has a powerful effect on diet and weight control. There is also evidence that diet can help or hinder sleep, depending on what foods you choose:
- A high-fat diet may contribute to disrupted sleep and excessive daytime tiredness, according to studies like this one.
- On the other hand, a vitamin and mineral-rich diet can both keep weight in check and promote healthy, restful sleep. Foods rich in magnesium and potassium -- including many fruits, vegetables, grains, and nuts -- improve circulation, and relax the muscles of the body. Research has shown that the gene that regulates potassium in the body may also be responsible for generating slow-wave sleep, the deepest and most restorative phase of sleep. Foods with calcium aid in the body's production of melatonin, a hormone critical to maintaining a healthy sleep-wake cycle.
- And it's not just what you eat, but when: the timing of meals and snacks relative to sleep can also have an effect on the quality of your eating and sleeping. People who have later bedtimes and eat more of their calories later in the day sleep less, consume more calories and have less healthful diets, according to this research.
Want your diet and your sleep to work together, each strengthening the other? Adopt a varied, nutrient-rich diet and a sleep routine that allows for seven to eight hours of nightly rest. Now that's a recipe for long-term health.
Michael J. Breus, PhD
The Sleep Doctor™
Everything you do, you do better with a good night's sleep™
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