We think a lot about how food benefits us, but can it sometimes have a negative effect on other processes in our body? This article looks into how not only what we eat, but when we eat, affects our quality of sleep.
It goes without saying that a nutrient-dense diet is beneficial for our health. Vitamins and minerals aid everyday bodily processes like hormone pathways and our metabolism. Studies have unsurprisingly shown that there is correlation between diets lacking in key micronutrients and issues with sleep, such as persistent sleep disturbances (1). Another unsurprising finding is the impact of alcohol on our sleep. Although many of us can find ourselves falling asleep very quickly after a few too many, once the alcohol starts to wear off we can often find that we're waking up frequently and struggling to get back to sleep (2).
Foods that can keep us awake longer than we'd like tend to be anything high in simple carbohydrates - usually sugary foods like biscuits and chocolate - and caffeine (3). Sugar consumption, particularly in the period leading up to bed time, has been shown to decrease deep sleep and increase disturbances (1). Changes to your blood sugar throughout the day - from consuming sugary foods - can make you feel tired which, if we give into this fatigue, can affect sleep patterns at night (3). Other studies support that meals low in fibre, high in sugar and high in saturated fat can also affect sleep (4) since these foods can irritate our digestive system.
Our body requires energy to digest food and so eating large meals close to bedtime can disrupt our sleep and make it more difficult to fall asleep (3). Given also that digestion tends to slow as we sleep, our body will work to keep us awake until our food has been significantly digested, which can take a couple of hours (4). If digestion continues throughout the night it can cause us to wake up frequently and hence prevent us from achieving deep sleep (5), which is incredibly important for our body to recover from daily strain.Studies show that eating larger meals within three hours before we try to sleep can increase sleep disruptions during the night and part of this can be influenced by acid reflux (4), something that often occurs if we overeat. Overeating in the evening can occur if we don't eat enough throughout the day. If you consume very little throughout the day, that hunger and energy demand will catch up and hence lead us to consume the greatest portion of our daily calories in the evening before bed. Instead, to improve our sleep, we should look to evenly spread our energy consumption throughout the day.
What is more, all of this can actually impact our circadian rhythm, which causes us to fall asleep at night and wake up in the morning. Our digestive system follows a similar rhythm: it expects to digest food during the day and, at night, our digestive system slows down significantly (5). Eating late at night triggers your metabolism to get back to work, which can disrupt both our digestive and circadian rhythms.
Despite all of this it's equally just as important to avoid going to bed hungry. There's nothing worse than lying in bed with your stomach rumbling, particularly given that it can be distracting and ultimately make it more difficult to fall asleep (3). Hence, we need to find a balance. That balance can vary from person to person and can often be down to a bit of trial and error. A large mixed meal 3-4 hours before bedtime and a small snack at least an hour before bed is often an effective solution, but think carefully about your snack. For example, remember that caffeine can impact our sleep quality... and chocolate contains caffeine! Consuming a small, high protein snack before bed could be the solution as it can not only fill you up but, studies have shown, it could improve muscle development overnight and increase your metabolism in the morning (6). Altogether it comes down to what works for you and what you think will best improve your sleep quality.
(1) Suni, E. 2020. Nutrition and Sleep. Sleep Foundation. Available from: https://www.sleepfoundation.org/nutrition [Accessed 27th October 2021].
(2) National Sleep Foundation. 2020. The Link Between Nutrition and Sleep. The NSF. Available from: https://www.thensf.org/the-link-between-nutrition-and-sleep/ [Accessed 27th October 2021].
(3) SleepScore Labs. 2016. Nutrition & Sleep: Relationship Between Diet & Sleep. Available from: https://www.sleepscore.com/blog/eat-well-sleep-well-how-diet-affects-your-sleep/ [Accessed 27th October 2021].
(4) Suni, E. 2020. Sleep and Overeating. Sleep Foundation. Available from: https://www.sleepfoundation.org/physical-health/sleep-and-overeating [Accessed 27th October 2021].
(5) American Sleep Association. n.d. Late Night Snacking and its Effect on Sleep. ASA. Available from: https://www.sleepassociation.org/blog-post/late-night-snacking-and-its-effect-on-sleep/ [Accessed 27th October 2021].
(6) Kinsey, A.W. and Ormsbee, M.J. 2015. The Health Impact of Nighttime Eating: Old and New Perspectives. Nutrients, pp. 2648–2662. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425165/ [Accessed 27th October 2021].