Lifestyle,  Nutrition

How Diet Affects Sleep

Research has shown that what we eat plays a significant role in regulating our hormones and the quality and quantity of our sleep.

Poor sleep can make it much more difficult to cope with stress and lowers our resilience. Recognising the connections between nutrition and sleep creates the opportunity to optimise both in order to sleep better and perform better. 

Foods that Interrupt Sleep


Caffeine is found in coffee, tea and many energy drinks and supplements. As a stimulant, caffeine would be one of the most well-known for interrupting sleep. How we metabolise caffeine is unique to each individual, staying in the system anywhere from 2-12 hours.

We can thank our genes for how fast or slow we metabolise caffeine. You may be someone who can drink coffee at 5pm and go to bed fine, falling asleep easily. If you’re like me, any caffeine in the afternoon leaves us awake and unable to fall asleep.

A gene called CYP1A2 determines the speed at which our body processes caffeine. CYP1A2 is an important detox enzyme found in the liver that breaks down toxins, drugs, hormones, and other products of metabolism in order to eliminate them from your body.

TIP: If caffeine does affect you, try to limit consuming to the early hours, with a lunch time cut-off. 

Refined Carbohydrates 

Refined carbohydrates are present in refined grains and refined sugars – such as white bread, tortillas, pastries, breakfast cereals, white rice, soft drinks, cakes, biscuits and sauces. Consuming these foods within 4 hours before bed causes an increase in blood glucose levels, making it difficult to fall asleep. The resulting drop in blood sugar leads to the release of the hormone’s adrenaline and cortisol, which then interferes with both falling and staying asleep. 


Alcohol is a central nervous system depressant, and many people use it to self-treat insomnia and induce sleepiness. However, drinking alcohol before bed has been shown to disrupt the duration of the different sleep cycles, such as REM-sleep, resulting in decreased sleep quality in the second half of the night.

Saturated Fat

Researchers found higher consumption of saturated fat was associated with shortened and more wakeful sleep during the night. Common foods high in saturated fat you should try to limit include chips, cakes, biscuits, processed deli-style meats and fried fast foods. Avoiding consuming these foods as much as possible will not only improve your sleep but your overall health, reducing inflammation and improving body composition.

Spicy Foods 

Eating spicy foods too close to bedtime can cause heartburn (this includes fatty foods), worsen sleep apnoea symptoms and increase your core body temperature, impacting your ability to fall sleep. Try to avoid spicy foods within 3 hours of bedtime. 

Avoid Large Meals Before Bed

It’s best to avoid large meals within 2-3 hours before bedtime. Being too full at bedtime can interfere with falling asleep and staying asleep throughout the night as the body works to digest. If you must eat before bed, a light snack like Greek yogurt, a banana, a small handful of almonds or pistachios or my warming Turmeric Milk is a good choice.

Try my warm turmeric milk recipe before bed to ease yourself into a deep slumber

Foods that Promote Sleep

Certain foods can help induce sleepiness. Consumption of nutrients such as antioxidants, carbohydrates and protein, B vitamins and magnesium increase our levels of tryptophan and melatonin, the main sleep hormone. Dietary sources of tryptophan include turkey, chicken, fish, eggs, milk, pumpkin seeds, beans, nuts, cheese, and leafy green vegetables.

Kiwi fruit – kiwi fruit are high in antioxidants and serotonin, our calming neurotransmitter that the body uses to synthesise melatonin. Just two medium sized kiwi fruit 1 hour before bed has been shown to significantly improve sleep onset, total sleep time and sleep efficiency were significantly increased.

Nuts – walnuts, almonds, pistachios and cashews are a good source of melatonin and are an excellent source of magnesium and healthy fats that promote sleep. Be mindful to keep it to a small handful.

brown wooden round bowl with white beans

Just 28 grams (that’s about 30 kernels) of pistachios contain about 6 mg of melatonin, which is similar to the amount found in the average melatonin supplement 

Herbal tea – try a cup of calming tea like chamomile or passionflower, that contain an antioxidant called apigenin, found to reduce anxiety and initiate sleep. I like to climb into bed at night with a cup of chamomile tea and a good book, silencing all devices, a warm (not hot) shower, and keep the lighting low.

Bananas – try a medium sized, slightly green banana with some protein like Greek yoghurt or natural nut butter. Bananas contain the amino acid L-tryptophan, which converts to 5-HTP in the brain. The 5-HTP in turn is converted to serotonin (a calming neurotransmitter) and melatonin. Try consuming about 1-2 hours before bed. A good alternative to high sugar content desserts.

Fatty fish – such as salmon, sardines, mackerel, and oysters are a good source of vitamin D and omega-3 fatty- acids, nutrients important for the regulation of serotonin.

Tart Cherries – contain high amounts of melatonin, with a recent study finding 2 x servings of 30ml concentrate increased sleep duration and decreased daytime napping. You can find unsweetened tart cherry concentrate at health food stores, stir into a glass of water if you find the concentrate too strong.

Sleep Hacks

  • Meditation and Yoga – activate your parasympathetic nervous system – the state of “rest and digest” with a restorative yoga practice or yoga nidra. Mindfulness based apps such as Insight Timer are a great aid to help you fall asleep and stay asleep. Guided meditations, sleep music, binaural beats, story telling audio’s and white noise can help to settle the busy racing mind.
Body scan meditation may help you fall asleep and stay asleep
  1. Journalling & gratitude practice – a simple gratitude practice literally re-wires your brain! With research finding that journalling just 2-3 times per week as effective as journalling daily. It doesn’t have to be complicated. It can be as simple as writing “I’m grateful for that delicious coffee I had this morning”. The act of writing your thoughts and feelings onto paper can be enough to shut off the to-do lists churning in your mind.
  2. Weighted blankets – people with chronic anxiety report success with weighted blankets. I’m seeing these become quite popular within the veteran community. Some people express they can feel overwhelming initially. It can be helpful to start with using the blanket on a small body part such as the arms or lower legs, then gradually increase the surface area.
  3. Bluetooth headband or sleep mask – these are a great option for an afternoon meditation or nap. Headband’s are a great option if you want to listen to meditation or music at night and don’t want to disturb anyone else.
  4. Warm bath or shower – a warm bath or shower 1 to 2 hours before bed can assist in raising your body temperature, as your body temperature drops sleepiness should set in. Research shows we fall asleep when our body temperature drops so don’t have your bedroom temperature or bedding too hot.
  5. No clock-watching! – this can be the hardest habit to break. Watching the clock and stressing with negative thoughts about not being able to fall asleep makes it even harder to fall asleep. If you haven’t fallen asleep within 20-30 minutes don’t fight it. Get up, make a cup of herbal tea, read something boring or pop on a guided meditation. As someone who has frequently battled with insomnia this works for me. I just accept those nights where I’m not going to fall asleep easily.
  6. Turn off devices – watching TV, working late on your computer, or playing on your phone or iPad at bedtime can make it more difficult to settle down for sleep. Try setting a time when you finish using your devices before bed. It can be helpful to set up a ‘charging station’ in another area of the house.

Keep a regular sleep routine, waking and going to bed at the same time each day. Adding a night time routine that feels right for you, gives your body the cue’s it needs that it’s time for sleep.