What is the effect of diet on your sleep?

When it comes to getting a good night’s sleep, recommendations include maintaining a regular bedtime and waketime, getting daily exercise, limiting caffeine and turning off screens an hour before tucking in.

What you might not consider, though, is what you eat during the day.

Why is 'sleep hygiene' important?

Growing evidence suggests that tweaking your diet can set you up for a better sleep. The foods you eat – and when you eat them – are thought to play a role in how well you sleep.

How much sleep do you need?

It’s recommended that adults get seven to nine hours of sleep each night. Children, ages 5 to 13, need nine to 11 hours of uninterrupted sleep and teenagers, ages 14 to 17, should get eight to 10.

According to the Public Health Agency of Canada, one in two adults have trouble going to sleep or staying asleep and one in five don’t find their sleep refreshing.

That was before the coronavirus pandemic, which, according to research from the University of Ottawa, has led to a sharp increase in sleep difficulties among Canadians.

Stress, anxiety, depression, disrupted daily schedules, excess screen time and sleep apnea, a disorder that occurs when a person’s breathing is interrupted repeatedly during sleep, are causes of poor sleep.

What are the effects of too little sleep?

Insufficient sleep is tied to an increased risk of obesity, type 2 diabetes, high blood pressure and cardiovascular disease. It can also impair cognitive performance, mood and immune function.

Being short on sleep can affect your diet, too. Studies show that people who are sleep deprived eat larger portions of food, snack more at night and are more likely to reach for high-carbohydrate and/or high-fat snacks.

Sleep loss increases the production of ghrelin, an appetite hormone that signals hunger to the brain. And when you’re overtired, your brain’s reward centre revs up, which can make you more likely to succumb to junk food.

Is there a link between diet and sleep patterns?

Research suggests that eating a healthy diet, plentiful in fibre-containing fruits, vegetables, whole grains and beans and low in refined carbohydrates and saturated fat, promotes a good night’s sleep.

A small trial from Columbia University in New York found that eating more saturated (animal) fat and less fibre during the day was associated with less time spent in regenerative sleep, the stage in which the body heals and repairs itself.

As well, participants who consumed more added sugars and refined starches during the day woke up often during the night.

These data suggest that your overall dietary pattern influences sleep quality.

Research from Boston University and Harvard Medical School, published in 2018, supports this.

Among 2,068 healthy adults, those whose diets closely matched the Mediterranean diet slept longer and were less likely to have insomnia than people who didn’t follow a Mediterranean diet.

Hallmark foods in the Mediterranean diet – fruits, vegetables, whole grains, beans, lentils, nuts, seeds, olive oil – contain anti-inflammatory nutrients, fibre and phytochemicals; inflammation in the brain is thought to contribute to poor sleep.

Plant foods and seeds also contain, at various levels, melatonin and serotonin, sleep-inducing brain chemicals.

Diet also plays a role in regulating our circadian rhythm, the 24-hour cycle that keeps all of our body’s functions running on time, including the secretion of melatonin to promote asleep. Certain nutrients are thought to be important, as well as the timing of when you consume them.

Research suggests that eating a carbohydrate-rich meal in the evening may delay melatonin release and the drop in body temperature that facilitates sleep.

Follow these three diet tips for better sleep:

1. Eat dinner at least three hours before bedtime and keep it light to prevent digestive upset during the night. Eating a fatty evening meal has been shown to cause sleep disruptions.
2. Avoid caffeine (coffee, tea, colas, dark chocolate) in the afternoon and evening if you have difficulty sleeping. Caffeine blocks the action of adenosine, a brain chemical that slows down nerve activity causing drowsiness.
3. Limit alcohol or avoid alcohol, which can cause you to wake up during restorative stages of sleep. Alcohol can also worsen sleep apnea symptoms.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD