How Your Diet Affects Your Sleep

Unfortunately, the timing and type of food we eat – nutrient deficiencies, eating too much, too little or too late, food intolerances and more – can hamper our sleep. Let’s break this fascinating subject down in more detail.

Mealtimes and the body clock

Our digestive system isn’t a 24-hour factory running at the same capacity all night. The gut and its accessory organs have their own body clock, timed to be most efficient in the day and early evening when our evolutionary ancestors were hunting, gathering and enjoying food. Like other hard-working organs and systems of the body, it needs time out for rest and regeneration. At night, hormones associated with eating, such as insulin (which regulates blood sugar) and numerous other digestive functions, wind down. Eating food within this timeframe can cause indigestion, blood sugar spikes and other symptoms that keep us up at night.

Studies comparing eating at different times show digestive function, metabolism, weight and sleep is superior when the majority of our calories are consumed earlier in the day (say, between 9am and 4pm) with the final meal being the lightest.

Time-restricted eating

Studies suggest the average person eats within a wide window of 15 hours daily. For those starting their first culinary experience at 8am, that means eating intermittently until 11pm!

Time-restricted eating, which is a form of intermittent fasting (fasting focused on when you eat), is an intentional way of confining your nosh to a tighter timeframe (as small as six hours). This usually cuts out one of the meals and some of the snacks you normally consume and helps you avoid eating at night.

Is it insomnia or your gut?

A study, published in Frontiers in Psychiatry, found six weeks of probiotics (beneficial bacteria) improved sleep quality for participants. And a 2020 study on rats found those who grazed on probiotics spent longer time in NREM sleep than the rats that didn’t. These are just some of the findings that show a direct link between the gut microbiome and our mood, sleep, food cravings, weight, immune health and more.

The gut microbiome is the ecosystem of trillions of bacteria that live in our gut. These tiny guys help produce hormones (like serotonin, GABA and dopamine) that promote a positive mood and regulate our sleep-wake cycle. Beneficial gut bacteria also dampen inflammation and preserve the health of the gut lining – helping reduce allergies, food intolerances and other problems with the potential to keep us up at night.

How to build asleep-friendly gut microbiome

Promote diversity:

A healthy gut microbiome, like any healthy ecosystem, is a “diverse” one. At least 1000 different bacteria species inhabit the gut, but many factors including age can cause them to decline. Balance is important to a healthy system: by wiping out the good bacteria, the bad guys (like garden weeds) can get the upper hand.

Avoid these:

Sugar, processed food, junk food, artificial additives, too many refined carbohydrates, food allergens, toxic chemicals including those found in many regular household cleaning products, pesticides, heavy metals, unnecessary antibiotics and pharmaceuticals and stress. These negatively impact the gut microbiome allowing pathogenic bacteria to thrive.

Enjoy prebiotics:

Prebiotics are non-digestible plant fibres that good bacteria preferentially feed off. The best sources include onions, garlic, leeks, Jerusalem artichoke, legumes and lentils, some nuts, green bananas, chicory root, dandelion greens, asparagus, avocado, flax and chia seeds, radishes, carrots, coconut meat or meal and raw oats. The larch tree is the source of many prebiotic supplements. If you eat a varied diet rich in fibre, vegetables and fruit, you’re likely to get a good variety.


These are the living, gut-friendly bacteria usually consumed as supplements and within fermented foods like yoghurt, sauerkraut, kimchi, kombucha, pickles, kefir, tempeh and miso. These add to your populations of beneficial bacteria.

Article featured in WellBeing: Your Sleep Coach

WellBeing Team

WellBeing Team

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