How Nutrition Impacts Sleep

Meal Timing for Better Sleep

Most evidence on how to enhance sleep through diet is anecdotal and thus not totally backed by science. For example, some people swear by a cup of herbal tea to help them sleep at night – but it’s unclear what helps with sleep onset, the herbs themselves or the relaxing ritual of sitting and drinking something hot.

That said, there are a couple of ways to enhance sleep through diet — mostly related to meal timing and limiting things that can interfere with sleep.

Meal Timing and Sleep Onset

“Circadian rhythms, metabolism, and nutrition are intimately linked, although effects of meal timing on the human circadian system are poorly understood,” a study published in the journal Current Biology in June 2017 explained. Translation: Meal times affect sleep, but the details aren’t totally clear.When to stop eating at night also depends on personal and professional schedules. Some people go to bed early and can stop eating at 6 p.m.; others are up until after midnight and would struggle with fasting for multiple hours before bed. LiveScience estimates that it takes the average person three hours to digest dinner and begin to feel hungry again, so a 2- or 3-hour buffer between dinner and bedtime seems reasonable.

Before reaching for a late-night snack, MIT recommends using the HALT acronym to establish a true motivation: Hunger, Anxiety, Loneliness, or Tiredness.” Instead of eating for a non-hunger reason, the site suggests, drink a glass of water or take a break to do something relaxing.

Meal Timing and Sleep Onset for Children

A pediatrician will be able to weigh in on diet recommendations for individual children and advise on whether commonly-held beliefs—like the idea that fatty fish is better for kids than meat in terms of improving sleep and mental health—hold any weight.

The Riley Hospital for Children at Indiana University Health explains that some kids will need a bedtime snack. “A kid who goes to bed hungry is going to have a tough time getting to sleep,” Dr. Stephanie Jackson, M.D., a pediatric neurologist, explains on the hospital’s website. “If you’re serving adequate portions at meals and your child consistently says she’s hungry at bedtime, a small snack is reasonable.”

Jackson recommends bedtime snacks that are high in protein or fiber, like “nuts, peanut butter, Greek yogurt, hummus, eggs, beans, tofu, berries, and whole grains.” It’s important for children to avoid caffeine before bed, which means that chocolate-y snacks are not recommended.

Finally, some kids may find it soothing to drink a glass of warm milk before bed. This protein-heavy snack can help keep them full through the night.

Is It Smart to Eat Carbs Before Bed?

Some research suggests that a high-carb meal can shorten sleep onset times. And where the carb foods fall on the glycemic index matters, too. The Academy of Nutrition and Dietetics explains that the glycemic index (GI) “is a measure of how quickly a food causes our blood sugar levels to rise.” GI is measured on a scale of 0 to 100, and “foods with a high glycemic index, or GI, are quickly digested and absorbed, causing a rapid rise in blood sugar… Meanwhile, foods with a low GI are digested and absorbed at a slower rate, and subsequently, cause a slower rise in blood sugar levels.”

A small study published in The American Journal of Clinical Nutrition in 2007 examined the relationship between carbohydrate intake and sleep. Researchers studied a group of 12 adult men aged 18-35 who had no known sleep disorders and did not take any medications. Each subject underwent three different test nights, with at least one week between each test night. On one night, they received a high-GI meal of jasmine rice four hours before their bedtime. On another, they received a high-GI meal of jasmine rice one hour before bedtime. On the final night, they received a low-GI meal of Mahatma rice, which has less than half the GI of Jasmine rice, four hours before bedtime.

Researchers found that the subjects fell asleep more quickly when they ate the high-GI meal. Furthermore, the high-GI meal eaten four hours before bedtime was more effective in shortening sleep onset than the high-GI meal eaten one hour before bedtime.

So, it’s possible that a high-GI meal can make it easier to fall asleep. However, because of the way high-GI foods affect blood sugar, experts typically recommend limiting the intake of high-GI foods. Plus, high-GI foods are often processed items like white bread or white rice, which are less nutritious than whole-grain options. Because of the effects on blood sugar, high-GI foods are often not suitable for people who have diabetes or other chronic health conditions. For instance, cancer patients have certain eating and digestion challenges of their own. 

“Eating healthier carbohydrates can help prevent a host of chronic conditions, especially diabetes, but it can also ward off heart disease and various cancers,” Harvard Health says. The occasional high-GI meal that fosters good sleep is probably nothing much to be concerned about, but relying on a carb-rich meal to fall asleep quickly every night is likely not a reasonable long-term solution to sleep onset problems.

Sleep Deprivation & Nutrition

Both sleep deprivation and nutrient deficiencies are common among American adults. New research suggests these two phenomena might be related.

The study, which was recently presented at the American Society for Nutrition’s Annual Meeting, Nutrition 2019, found that people who obtained fewer than seven hours of sleep per night, on average, consumed lower amounts of certain vitamins and minerals compared to people who slept more than seven hours per night.

Additionally, the study suggests that certain nutrient deficiencies may be associated with poor sleep quality, trouble falling asleep, and even sleep disorders.

Dr. Chioma Ikonte, lead author of the study and Director of Nutrition Sciences at Pharmavite LLC—a company that sells dietary supplements and funded this study—told Mattress Clarity via email:

“This research was inspired by the fact that most Americans fall short of the Center for Disease Control (CDC) recommended sleep hours of 7 to 9 hours for adults 18 to 64 years. A number of studies have also reported on the inadequate intakes of several micronutrients across the American population. We wanted to understand if there was a relationship between nutrient intakes and sleep outcomes. 

We performed a cross-sectional analysis of the NHANES database from 2005 to 2016, which assessed the intake of micro and macronutrients from food and food plus supplements among individuals 19+ years who self-reported various sleep issues. The sample size for this study was more than 26,000 Americans.”

This analysis found that people who obtained, on average, less than seven hours of sleep per night consumed lower amounts of vitamins A, B1, and D and the minerals calcium, magnesium, niacin, phosphorus, and zinc. The new study adds to a growing body of research suggesting that sleep quality and nutrition may be closely linked.

Sleep Deprivation Can Contribute to Dietary Choices

An October 2019 study found that sleep deprivation affects the type of foods people choose to eat. Researchers followed a group of 29 men and women over two different nights four weeks apart: During one night, participants got a normal night’s sleep. On the other night, they were only permitted to sleep for four hours total. The day after, participants were served three meals, but also offered a buffet of different snack options including less-nutritious foods.

After being sleep deprived, researcher Thorsten Kahnt, an assistant professor of neurology at Northwestern University Feinberg School of Medicine, said in an article: “We found participants changed their food choices. After being sleep deprived, they ate food with higher energy density (more calories per gram) like doughnuts, chocolate chip cookies, and potato chips.”

Kahnt suggests that this is because “sleep deprivation makes our brain more susceptible to enticing food smells.” He joked: “So maybe it might be worth taking a detour to avoid your local doughnut shop next time you catch a 6 a.m. flight.”

Sleep Deprivation Can Influence Sugar Cravings

Those looking to cut out sugar, getting more sleep could help. A study published in the American Journal of Clinical Nutrition found a link between getting more sleep and consuming less sugar.

A group of 42 people aged 18 to 64 who slept between five and seven hours each night took part in the study. The “sleep extension” group were given a 45-minute consultation about how to get a better night’s’ sleep, whereas the “control” group did not. All the participants wore sleep trackers and kept food diaries for the duration of the four-week trial.

The sleep consultations, which were led by a sleep psychologist and involved setting bedtimes and sleep-promoting behavior like avoiding electronics before bed, seemed to work for the “sleep extension” group: 86 percent of them increased the average time they spent in bed, and 50 percent increased their average time asleep by between 52 to 88 minutes.

Researchers also noticed an interesting side effect: Participants who increased their sleep also reported eating less sugar. They wrote in the study that “sleep extension led to reduced intake of free sugars” by an average of 10 grams per day.

Weight & Sleep

There are two major components to dieting: Weight loss and exercise. Experts say that the key to successful weight loss in maintaining a calorie deficit, meaning more calories are burned than are consumed. Another, less obvious factor in successful weight loss? Sleep.

A paper in the peer-reviewed journal Obesity Reviews, published in 2017, examined the connection between stress, poor sleep, enhanced appetite, food cravings, and motivation towards physical activity. They found that stress affected all of these things, and also noted that inadequate sleep is linked to obesity.

“Not only do the adverse effects of stress influence sleep patterns, food intake, weight gain, abdominal obesity and the effects of weight loss interventions but evidence also suggests that improving nutritional status and sleeping patterns may reduce the severity of stress and other mental disorders,” study researchers wrote.

Weight Can Affect Sleep Disorders

Bodyweight plays a role in many facets of health, including sleep disorders. The American Sleep Apnea Association stresses that being overweight or obese is not the only reason why someone might develop sleep apnea, but notes that “being overweight is still a high risk factor for the development of obstructive sleep apnea.”

The American Academy of Sleep Medicine (AASM) defines obstructive sleep apnea as “a sleep-related breathing disorder that involves a decrease or complete halt in airflow despite an ongoing effort to breathe.” This happens when the soft tissue in the back of the throat blocks the upper airway, pausing or halting breathing for 10 seconds or more — up to even one minute or longer.

“The brain responds to the lack of oxygen by alerting the body, causing a brief arousal from sleep that restores normal breathing,” the AASM says. This pattern can occur hundreds of times in one night. The result is a fragmented quality of sleep that often produces an excessive level of daytime sleepiness.”

Other risk factors that contribute to obstructive sleep apnea include a narrow airway, chronic nasal congestion, high blood pressure, smoking, family history, diabetes, and a smoking habit. However, the Mayo Clinic says that most people with obstructive sleep apnea are overweight or obese.

“Excess body weight contributes to sleep apnea by causing increased pressure on upper airways, leading to collapse and decreased neuromuscular control from the fatty deposits,” the Obesity Medicine Association says. “These fatty deposits contribute to decreased lung volume and make it more difficult to breathe.”

For milder cases of obstructive sleep apnea, doctors may recommend lifestyle changes like weight loss. Other potential treatments include sleeping with a continuous positive airway pressure (CPAP) mask, wearing a mouthpiece, or undergoing surgery.

“If you’re overweight or obese, even a moderate loss of excess weight may help relieve constriction of your airway,” the Mayo Clinic says. “Losing weight can also improve your health and quality of life, and may reduce your sleepiness during the day.”

The Bottom Line

The relationship between food and sleep is incredibly complex and varies from person to person. Everyone has an individual tolerance for caffeine and alcohol and digests food at different rates.

This means that foods or mealtimes that affect sleep for one person will have no effect on another.

Following a nutritionally balanced, healthy diet can improve overall health and sleep habits. Consult a doctor for any specific concerns about the intersection between diet and sleep.

Further reading:

• Foods and Sleep – Mayo Clinic
• Improve Sleep by Eating Right – Harvard Health
• The University Of Iowa — Is Your Diet Keeping You Awake?
• Stanford — to Fight Effects of Sleep Deprivation, Reach for Healthy Snacks
• Better Sleep: 3 Simple Diet Tweaks | Johns Hopkins Medicine
• Sleep Deprivation and Obesity | The Nutrition Source

Featured image: G-Stock Studio/Shutterstock