While it's long been known that late night meals and too much caffeine can disrupt your sleep, research now shows that the type of food we eat throughout the day can also influence our sleep quality.
A new study by Japanese sleep scientists has found greater protein and fiber intake is associated with sleeping longer and getting better quality sleep compared to other macronutrients like fat and carbohydrates.
The study correlated daily data from sleep and diet tracking mobile apps to investigate the relationship between macronutrient intake and sleep outcomes, concluding that protein and fiber are the most sleep-friendly food groups.
Protein can be found in meats, fish, beans, nuts and dairy; while fruits, vegetables, whole grains, legumes, nuts and seeds are laden with fiber. But how do these foods boost your kip? Lets take a closer look at the new findings.
Key findings from the study:
- Increasing protein intake can bag you 18 minutes more sleep
- Just a 6% increase in protein showed positive sleep outcomes
- Fiber intake consistently associated with improved sleep onset and quality
The researchers analyzed data from 4,825 users of the Pokémon Sleep and Asken smartphone apps, each used for at least 7 days to record objective sleep parameters and dietary components, respectively.
Increasing protein intake was associated with longer sleep duration. A 6% rise in protein increased total sleep time by 0.3 hours — that's 18 minutes more sleep.
Meanwhile, replacing protein with carbohydrates reduced sleep time by 0.2 hours (12 minutes).
A 6% rise in protein increased total sleep time by 0.3 hours — that's 18 minutes more sleep
Regarding sleep latency, adding more protein and taking away monounsaturated fat in the participants' diets resulted in an average decrease in time taken to fall asleep by 3 minutes and 42 seconds.
What about waking up during the night? Replacing fat with protein saw a 1.8% decrease in wakefulness after sleep onset.
Additionally, dietary fiber intake was consistently associated with improved sleep latency and reduced nighttime awakenings, improving overall sleep architecture and quality.
How protein helps you fall asleep fast and stay asleep
The macronutrient loved by gym bros, protein's primary function in the body is to build and repair muscle tissues. But it has uses beyond making your biceps pop, including aiding sleep quality.
"The mechanism by which proteins affect sleep following acute feeding may involve tryptophan; tyrosine; and the synthesis of brain neurotransmitters, such as serotonin, melatonin, and dopamine," the study authors concluded.
Tryptophan is an amino acid that helps regulate sleep and can be found in foods including almonds, avocado, turkey and cottage cheese.
Meanwhile, serotonin and dopamine work alongside the sleepy hormone melatonin to promote sleep.
These neurotransmitters send chemical messages in the brain, helping to regulate sleep-wake cycles so you feel energetic and alert during the day and sleepy at night.
How fiber helps you fall asleep fast and stay asleep
Fiber-rich foods help regulate blood sugar levels, promote satiety and support healthy digestion, all of which can help you get deeper, more restorative sleep.
Helping to maintain stable blood sugar levels and keep you feeling full, eating plenty of fiber reduces the chance of nighttime awakenings caused by hunger pangs.
Digestive issues like bloating, stomach pain, heartburn and the need to use the bathroom can also cause discomfort through the night, disrupting your ZZZs. Therefore, by supporting your digestive system, fiber helps you sleep better.
Your gut and brain are closely linked. Studies suggest that dietary fiber can affect sleep by influencing microbiota. This is because gut microbes inform the production of sleep-regulating hormones.
When dietary fibers are fermented by microbiota in the large intestine, they enhance serotonin release. Serotonin helps regulate the sleep-wake cycle by contributing to the synthesis of melatonin, the hormone that induces sleep.
How to optimize your diet for better sleep
Food plays a huge role in our ability to sleep and the quality of rest we get. If you're struggling to sleep, altering your diet can make a big difference. Here's three small changes that can help you get quality slumber...
Eat three balanced meals a day
A balanced diet, comprising all essential vitamins, nutrients and food groups, is key to maintaining good health and that includes healthy sleep function.
Our parents were right when it comes to the three meals a day rule as it helps blood sugar stability, circadian rhythm regulation and digestive health, which all contribute to good sleep.
Eating three balanced meals at consistent times throughout the day helps regulate your body's internal clock and sustain your energy levels.
This means you're more likely to feel sleepy when it is time to wind down for bed, helping you establish an efficient sleep pattern.
Finish your last meal 2 hours before bed
Large meals late in the evening can make it more difficult to fall asleep and provoke more frequent nighttime awakenings.
This is because consuming large amounts of food spikes cortisol levels and raises body temperature which makes falling alseep harder.
If you head to bed while still digesting your last meal, your body will find it harder to wind down. Essentially, it still has work to do (digesting the food) so switching off to sleep is not as seamless.
Plus laying down after a meal means stomach acid can easily travel back up your oesophagus, causing heartburn and discomfort, making it harder to find a comfortable sleep position, even on the best mattresses.
Opt for healthy, sleep-inducing nighttime snacks
When we spoke to Shelley Balls, MDA, RDN, LDN, a registered dietitian and nutritionist about the best nighttime snacks that help you sleep better, she recommended sticking with wholegrains, calcium-rich dairy products, cherries and almonds and avoiding high-sugar sweet treats, spicy foods and stimulants like alcohol and caffeine (no surprise there).
Hence, a slice of toast with avocado, a glass of milk, popcorn or vegetable sticks and a fiber-full dip like hummus or cottage cheese are all great bedtime snacks.
