The connection between diet and sleep

Diet and sleep

Sleep plays a significant role in our diet, says Olivia Morrison, Accredited Practicing Dietitian and nutritionist at No Worries Nutrition. “When we don't sleep enough, our hunger hormone ghrelin skyrockets and our satiety hormone leptin significantly drops; prompting us to eat more,” she says.

Poor sleep can also cause us to super-size our portions and crave carbohydrates – it’s our body’s way of finding energy from calories.

“Further, studies have consistently shown that eating too late at night disrupts our sleep quality and significantly contributes to developing chronic disease,” says Morrison.
The ideal duration is typically seven to eight hours of shut eye, says Lulu Cook, Accredited Practicing Dietitian and health coach.

“This is the amount of sleep that’s been found to correlate with the best health outcomes including weight management and minimizing inflammation,” she says.

Before we break into the specifics, it’s safe to say you can never go wrong with foods that are slow releasing energy sources, such as proteins, fibre-rich vegetables and grains, and also fats, when it comes to promoting sleep, says Tracie Connor, Accredited Nutritionist.

“They allow the body to relax without a sharp rise in insulin and also filled with nutrients to nourish the body and mind,” she says.

Conversely, foods or drinks high in caffeine, are highly refined, or have little nutrients and filled with sugar raise insulin levels and act as stimulants that don’t allow the body to rest well, she says. “Alcohol can also inhibit quality sleep, so if you plan to drink its best to drink a few hours away from sleep. It dehydrates and disturbs the REM phase of sleep.”

Carbohydrates

Research suggests the quality of carbs we consume are linked to for sleep quality and length, and Cook says those that are higher in fibre rather than simple sugars will promote a more restful sleep.

“Fibre increases the amount of time spent in restorative slow-wave sleep, while decreasing added sugars and saturated fats also helps ensure that it’s easy to fall asleep, rest deeply, and clock the ideal duration of sleep,” she says.

'Low GI' carbohydrate – those that digest slowly providing your body with long lasting fuel such as quinoa, basmati rice, sweet potato, legumes, pulse pasta, colourful vegetables are a good choice for a healthy, sleep promoting diet, says Morrison.

Added sugar and saturated fats

Diets high in added sugars tend to be lower in nutritional quality overall and may be an indicator that an individual is missing out on the slow-burn carbohydrates and healthy proteins that promote better sleep, says Cook.

“Added sugars are also often found in high-fat foods, which may likewise negatively impact sleep. Finally, there may be hormonal and metabolic effects of those sugary foods and drink related to blood sugar regulation that impair sleep quality,” she says.

Protein

“Something I recommend to clients that struggle with sleep is ensuring adequate and quality protein intake throughout the whole day,” says Morrison. She says spacing when you eat your protein can help control sugar cravings, portions and energy levels as it helps slow digestion.

“I recommend choosing lean sources of quality protein; free range eggs, cottage & ricotta cheese, chicken breast, tofu, legumes, occasional lean beef.”

Quantity also matters, Cook says the research suggests we want to look for the ‘sweet spot’ with protein intake to promote sleep – not too little, and not too much.

For most healthy adults, two to three serves of protein each day is enough, however if you're very tall or exercising at high intensity more than twice a week, you may benefit from speaking to an accredited dietitian, says Morrison.

“Proteins are the source of amino acids, from which sleep hormones including melatonin are made. It’s also helpful if the protein sources we select are lower in saturated fats, making plant-based proteins a good choice,” Cook says.

What about foods containing trytophan?

Anyone who has struggled with sleep and turned to the internet for diet and sleep related advice has no doubt come across advice to consume tryptophan – contained in foods such as turkey and pumpkin seeds, for example. However, the jury is still out.

It plays an indirect role in regulating mood and sleep as its the precursor of one of our main happy and wakefulness hormones, serotonin, production of which increases production of sleep hormone melatonin, says Morrison.

However, whilst it’s important to have enough of the amino acid tryptophan for production of sleep-regulating hormones melatonin and serotonin, it does not appear that purposefully amping up on high-tryptophan foods before bed is likely to bring on sleep any faster than other nutritious snacks might, Cook says.

Conversely she says tart cherries have been linked with enhanced sleep quality, adding grapes are source of sleep-regulating melatonin, and kiwifruit provide a good boost of serotonin, a calming hormone.

As always, a healthy, balanced diet is best

“The overall dietary pattern a person follows will always be more powerful in regards health effects than any individual ingredient would be,” says Cook. The Mediterranean diet, which is high in less-processed vegetables, legumes, nuts, and healthy fats is consistently linked with better sleep quality, Cook says.

A well-balanced diet also promotes good gut health, which influences sleep. It’s also important to avoid foods that disrupt the balance of good bacteria – diets heavy on sugars, alcohol, tobacco cigarettes, fatty and highly-processed foods aren't great for gut heath, Morrison says.