From Sugar to Caffeine: 8 Foods That Keep You Awake at Night
Not getting enough sleep at night can leave you feeling irritable and tired the next day, and if it happens regularly, it can also cause more long-term issues. As well as affecting cognition, concentration and mental resilience, poor sleep has been linked to chronic illnessi and cardiovascular problems. Nutrition and eating patterns play a crucial role in sleep hygiene, and some of the foods you are eating could be playing a role in keeping you awake at night.
Here, we outline eight foods that can disrupt sleep along with some sleep-healthy suggestions.
How does digestion relate to poor sleep?
Like your brain, your digestive system is programmed to rest at night-time. Meaning that if you eat too close to your bedtime, your digestive system isn’t best prepared to process it. As a result, you may experience uncomfortable digestion symptoms that can disrupt your sleep, such as constipation, bloating, and acid reflux. You should aim to eat at least two to three hours before you go to sleep to avoid this, but it’s important to also consider which foods you are eating.
Which foods keep you awake at night?
A psychoactive stimulant, it’s well-known that caffeine disrupts sleep. This is because caffeine increases levels of cortisol, which functions inverse to your sleep hormone, melatonin, needed to sleep. Your melatonin and serotonin hormones are essential in helping you fall asleep.
In addition, caffeine has an average half-life (the time it takes for half of it to be excreted from your system) of six to seven hours. To put this into context: if you have a cup of coffee after your evening meal at 7 pm, by 1 am, 50 per cent of the caffeine is still circulating around your brain tissue. One study found that subjects who were given roughly four cups of coffee, anywhere from 0-6 hours before bed, experienced significant sleep disturbances.ii
To improve your sleep hygiene, avoid consuming caffeine after midday. As an alternative to coffee, try to drink non-caffeinated/herbal teas, and decaffeinated coffee in the afternoon. Dark chocolate and energy drinks also contain varying amounts of caffeine.
There are two main reasons why you should avoid alcohol before sleep. Firstly, studies suggest that alcohol fragments your sleepiii. As the sedative properties of alcohol wear off, your body experiences a ‘rebound’ effect, which causes frequent awakenings. As a result, you will wake up without having benefited from a deep sleep.
Secondly, alcohol blocks your REM sleepiv, the deepest stage of sleep where you dream. REM sleep is essential for emotional wellbeing, supporting your mood and mental health.
As such, you should limit yourself to two ‘drinking days’ per week, and be mindful of what time you drink alcohol. Try drinking at the traditional ‘happy hours’ — between 5 and 7 pm — as it takes an hour to process each serving of alcohol. Always drink two glasses of water for every beverage to flush out the alcohol and promote quality sleep.
Read this article to find out more about the science behind how alcohol affects sleep.
According to an Australian study, the capsaicin in chilli peppers and other spicy food elevates your core body temperature, which needs lowering to fall asleep.v Spicy foods also irritate your stomach and can cause heartburn, acid reflux, and indigestion. The resulting pain and discomfort can make it much harder to fall asleep.
To avoid digestive upset before bed, try to consume spicy food earlier in the day. This way, you allow more time for digestion before bedtime.
Heavy fatty food
A number of studies suggest that eating fatty foods — fast food, processed meat, fried food, baked goods, and coconut oil — before bed can interfere with sleep and alter your circadian rhythm.
One study discovered that, after eating high-fat foods, participants experienced less REM sleep,vi while another showed it took longer for its participants to reach this stage entirely.vii Researchers at Columbia University also revealed that people who eat a diet rich in saturated fat and low in fibre are at a higher risk of experiencing more night-time arousals and lighter sleep.viii
Where possible, use whole foods in your evening meals, with a balance of protein, healthy fats, and complex carbohydrates. Instead of frying food, try steamed, grilled, sautéed, or baked preparation.
Evidence suggests consuming sugar before bed can lead to restless sleep. In the aforementioned study, researchers found volunteers who ate significantly more sugar spent less time in deep non-REM sleep.viii This phase of sleep is essential for healing, physical restoration, immunity, and metabolism. The participants who consumed more sugar also took longer to fall asleep and experienced a more restless night overall.
If you have a craving for sugar before bed, choose a banana over anything refined. Bananas are naturally sweet and full of sleep-promoting magnesium.
Foods with Tyramine
Fermented foods, like aged cheeses (cheddar, Brie, blue cheeses, Gouda for example), sour cream, and yoghurt all contain the amino acid Tyramine. This amino acid stimulates the release of norepinephrine, a brain stimulant, which may make you less able to fall asleep.ix
Fresh cheese doesn’t contain as much Tyramine as aged cheese, so if you have a craving, try to stick to these cheeses.
Juicy fruits and vegetables
Despite being nutrient-dense, juicy fruits and vegetables are full of water, which can induce diuresis throughout the night. In particular, cucumber, melon, strawberries, oranges, peaches, and celery all have extremely high water content.
Make a conscious effort to consume these foods earlier in the day. Otherwise, you may wake up during the night needing the bathroom, interrupting your sleep.
Cauliflower or broccoli
Eating cruciferous vegetables, like cauliflower or broccoli, has been linked with poor sleep. Although these vegetables contain a small amount of tryptophan, eating them too close to bedtime can disrupt your rest as they take a long time to digest. These foods keep your body working well into the night when you’re trying to sleep.
Like the fruit and vegetables mentioned above, try to limit your consumption of these foods to earlier in the day.
By making small changes to your diet and nutrition, you can improve your sleep hygiene and wake up feeling energised.
Everyone needs quality sleep to function. If you would like to learn more about your sleep hygiene, explore our dedicated resources on sleep health.
Cappuccio. F., D'Elia. L., Strazzullo. P. & Miller. M. (2010). Sleep Duration and All-Cause Mortality: A Systematic Review and Meta-Analysis of Prospective Studies. Sleep. 33(5), 585-592.
Drake. C., Roehrs. T., Shambroom. J. & Roth. T. (2013). Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed. Journal of Clinical Sleep Medicine.
Stein. M.D. & Friedmann. P.D. (2005). Disturbed sleep and its relationship to alcohol use. Substance abuse. 26(1), 1–13.
Ebrahim. I., Shapiro. C., Williams. A. & Fenwick. P.(2013). Alcohol and Sleep I: Effects on Normal Sleep. Alcoholism: Clinical and Experimental Research. 37(4), 539-549.
Edwards. S., Montgomery. I., Colquhoun. E., Jordan. J. & Clark. M. (1992). Spicy meal disturbs sleep: an effect of thermoregulation? International Journal of Psychophysiology. 13(2), 97-100.
Lyytikäinen. P., Kyröläinen. H., Rahkonen. O., Lahelma. E. & Lallukka. T. (2010). Association of sleep duration with weight and weight gain: a prospective follow-up study. Journal of Sleep Research. 20(2), 298-302.
Crispim. C., Zimberg. I., dos Reis. B., Diniz. R., Tufik. S. & de Mello. M. (2011). Relationship between Food Intake and Sleep Pattern in Healthy Individuals. Journal of Clinical Sleep Medicine.
St-Onge. M.P., Roberts. A., Shechter. A. & Choudhury. A.R. (2016). Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine. 12(1), 19–24.
Pubchem.ncbi.nlm.nih.gov. (2019). Tyramine. Available online: https://pubchem.ncbi.nlm.nih.gov/compound/Tyramine
Olivia Salter has always been an avid health nut. After graduating from the University of Bristol, she began working for a nutritional consultancy where she discovered her passion for all things wellness-related. There, she executed much of the company’s content marketing strategy and found her niche in health writing, publishing articles in Women’s Health, Mind Body Green, Thrive and Psychologies.