The surprising links between how well you sleep and what you eat

Not getting enough sleep can lead to a vicious cycle of overeating and further sleep deprivation, but it may be possible to create a virtuous cycle, where healthy eating improves sleep.

Tania Whalen finds it impossible to get enough sleep, as she works nights and early mornings at the fire station in Melbourne, Australia.

To make it through the long nights answering emergency calls and dispatching crews, he often brought snacks to work.

“Could be a muffin or some cookies to eat on a break because I was a little hungry or wanted to boost my energy a little,” he says.

In addition, he usually bought chips or chocolate from the vending machine at the fire station.

He knew his diet wasn’t doing him much good. She was gaining weight, and yet it was hard to resist.

Tania’s behavior was not unusual.

When one has not rested enough, one longs to eat.

“There are some diabolical changes in the brain and body when you sleep too little that lead to overeating and thus gain weight,” says Professor Matthew Walker, director of the Center for Human Sleep Science at the University of California.

It’s true that when we’re awake longer we need more energy, but not as much: sleep is a surprisingly active process during which our brains and bodies work hard, Professor Walker explains.

Despite that, when we don’t sleep, we tend to overeat more than double or triple the number of calories we need.

This is because sleep affects two hormones that control appetite, leptin and ghrelin.

Leptin tells your brain that you’ve had enough to eat. When leptin levels are high, our appetite is reduced. Ghrelin does the opposite: When ghrelin levels are high, you don’t feel satisfied with the food you eat.

Experiments have shown that when people don’t sleep, these two hormones go in opposite directions: there is a marked drop in leptin, which means increased appetite, while ghrelin skyrockets, leaving people feeling unsatisfied.

It’s like a double jeopardy, says Walker. “You are being punished twice for the same crime of not getting enough sleep“.

Why does that happen?

Walker thinks there is an evolutionary explanation.

Animals are rarely sleep deprived unless they are hungry and need to stay awake to find food. So when we don’t get enough sleep, from an evolutionary perspective, our brain thinks we may be in a state of starvation and increases our food cravings to prompt us to eat more.

And not getting enough sleep not only affects how much we eat, but also what we eat.

A study by Walker showed that participants had more cravings for sugary, salty, and carbohydrate-rich foods when they weren’t sleeping well.

None of this is good news for tired night shift workers like Tania Whalen.

In fact, the situation may be even worse for them, since it’s not just what they eat that’s the problem, but also when they eat it.

The experiment

Our bodies are set up to keep going in a 24-hour rhythm, says Maxine Bonham, Associate Professor of Nutrition, Dietetics and Food at Monash University in Melbourne.

“We’re supposed to work, eat and exercise during the day, and sleep at night, and our body is set up to do that. So when you work a night shift, you are doing the opposite of what your body expects“.

That means we have a harder time processing food when we eat at night, which can lead to higher glucose levels and more fatty substances in the blood, since the body is less able to break down and metabolize nutrients, says Bonham.

Night shift workers are known to be at increased risk of weight gain, type 2 diabetes and cardiovascular disease.

Also, they are more likely to be overweight.

Bonham and his colleagues conducted an experiment to see if they could help people who work night shifts lose excess weight and improve their overall health.

They recruited about 220 shift workers who wanted to lose weight and put them on a variety of diets over a six-month period.

Tanya

The experiment

Our bodies are set up to keep going in a 24-hour rhythm, says Maxine Bonham, Associate Professor of Nutrition, Dietetics and Food at Monash University in Melbourne.

“We’re supposed to work, eat and exercise during the day, and sleep at night, and our body is set up to do that. So when you work a night shift, you are doing the opposite of what your body expects“.

That means we have a harder time processing food when we eat at night, which can lead to higher glucose levels and more fatty substances in the blood, since the body is less able to break down and metabolize nutrients, says Bonham.

Night shift workers are known to be at increased risk of weight gain, type 2 diabetes and cardiovascular disease.

Also, they are more likely to be overweight.

Bonham and his colleagues conducted an experiment to see if they could help people who work night shifts lose excess weight and improve their overall health.

They recruited about 220 shift workers who wanted to lose weight and put them on a variety of diets over a six-month period.

Tanya

Tania Whalen, the fire dispatcher, signed up for a fasting program: For two days a week, she had to consume just 600 calories in 24 hours.

“It was tough,” says Tania. “I was worried I wouldn’t be able to do it. Sometimes a 12-hour shift seemed to last 20.”

But he stood his ground, distracting himself by reading, playing games, going for walks, and drinking gallons of mint tea.

The results of the study are not yet available, but Tania feels that it has been a positive experience that prompted her to make other changes; for example, she now walks 5 km every day.

“I certainly have more energy and more desire to move, and I have lost a considerable amount of weight“, it says.

Interestingly, Tania believes it has also helped her sleep better.

“Even in the limited hours I have, I don’t walk as much and have almost completely stopped snoring, says my husband.”

It’s not clear if this improvement is due to the new diet, exercise, weight loss, or something else entirely, but it does raise the question of whether what you eat can affect the way you sleep.

Eat to sleep?

So far we’ve talked about how sleep, or the lack of it, can affect what you eat. But what if you could eat to get a good night’s sleep?

Marie-Pierre St-Onge, a researcher at Sleep and Nutrition in New York, had spent years studying the impact of sleep deprivation on diet when, in 2015, she was contacted by a committee that wrote the Dietary Guidelines for Americans. Should they advise people what to eat to improve their sleep?They Asked.

“My first reaction was, ‘Why didn’t I think of that?'”

Melatonin, the sleep-promoting hormone that rises at night, comes from a dietary amino acid called tryptophan.

“If the hormone that regulates sleep is produced entirely from an amino acid that must be consumed in the diet, then it makes sense that diet is important in regulating sleep“, it says.

And yet, St-Onge was unable to find any studies focused on this relationship. So she and her team began looking into research on other health issues, which had recorded the dietary and sleep habits of the participants.

Examining that data, a clear pattern emerged.

The Mediterranean

People who followed a Mediterranean diet (who ate lots of fruits and vegetables, fish, and whole grains) had a 35% lower risk of insomnia than those who didn’t, and were 1.4 times more likely to get a good night’s sleep .

So what is it that induces sleep in that diet?

foods like fish, nuts, and seeds are high in melatonin-producing tryptophan.

And several small studies have shown that specific foods, such as tomatoes, tart cherries, and kiwi, that contain melatonin, can help people fall asleep more easily and stay asleep longer.

There are also foods that should be avoided before bedtime.

Most people know about caffeine, which is a stimulant, but they may not realize that salty foods can make you thirsty, which can disturb your sleep.

St-Onge’s study also indicates that eating sugary foods can lead to a more disturbed night. His team is investigating why that might be.

Studies examining the influence of food on sleep are still few and small, so St-Onge says more research is needed before they can be taken as scientific fact.

However, they do raise the possibility that eating certain foods can help us sleep better.