Written by Lizzie Davies. Lizzie is a final year student dietitian at King’s College London. Her current interests in dietetics include women’s health and cystic fibrosis. In her spare time, she loves to bake and cook, and volunteers in the charity sector. Find her on Instagram @lizziedietetics.

 

Whether you are someone that religiously gets a full 8 hours, or if you regularly survive on coffee to get through the day after ‘one more minute’ of scrolling on your phone, we all need sleep, and it is an important part of our lives no matter how inconvenient it sometimes may seem. There is now lots of varied research showing the many possible effects of how sleep impacts our physical and mental health, with a lack of sleep increasing our risk for diseases such as cardiovascular disease, metabolic syndrome and even dementia (1).  Even if you are someone who feels okay on less than the recommended 7-9 hours of sleep (2), you are probably not as invincible as you believe, as it may be impacting you in ways you don’t consciously realise. There are many well-known lifestyle factors associated with how well we sleep including the quantity and quality of sleep, caffeine, alcohol and exposure to light affecting our circadian rhythm (2). A lesser known but still important factor to how we sleep is nutrition, which has a bi-directional association with sleep, meaning that what we eat can affect how we sleep, and how we sleep can affect what we choose to eat.

Why do we all sleep differently? 

We all have different sleep needs and preferences, whether it be a certain type of mattress or rituals like having a warm shower or a mug of herbal tea or hot chocolate, and these are all personal to us and may be formed out of habit. The definition of being sleep deprived isn’t clear, with some studies using anything <8 hours, or some even defining as short as <4 hours. Furthermore, it is believed that we have sleep ‘chronotypes’ in which we are essentially wired to function better with different sleep times and wake/work times. Some of us may prefer to sleep late and wake later, whilst some may be true morning people, and some are somewhere in-between. These differences are thought to have some link to genetics (3). Unfortunately, society is generally geared towards morning people, meaning that evening people may sleep later but still must wake up early for their 9-5, leaving them sleep deprived. Shift workers also get a bad deal when it comes to sleep, having to adapt to completely different sleeping patterns all the time, which could also lead to sleep deprivation.

Generally, people are becoming more aware of how much they are sleeping, and how this may be affecting their health. This may be due to increased research and conversation, as well as the rise in popularity of smart watches, which can track sleep length and quality, as well as other sleep apps to track sleep- including ones with meditation, white noise and night-time journaling. The concept of sleep debt is also quite popular, which is where a device calculates how much sleep you have missed and thus how much sleep you should catch up on to effectively clear the debt, but this doesn’t have much of an evidence base.

Sleep deprivation and food choices 

We’ve all been there, when after a long flight or bad sleep, all we want to do is reach for the food that is going to give us the most energy and in the quickest way possible. Whether you reach for the ramen in your cupboard or redownload the food delivery app you swore you’d give up to save money, did you know that there is lots of research about how sleep deprivation affects our food choices? Multiple studies actually show consistent associations between short sleep duration and higher total energy intake as well as higher fat intake (4, 5). There is also some evidence to suggest a lower overall quality of diet with lower fruit intake (4). Of course, a night here and there of poor sleep is acceptable and sometimes unavoidable, but the problem exists when people are chronically sleep deprived, as these dietary habits along with a tendency for decreased or unchanged energy expenditure, could lead to weight gain, obesity and associated diseases (5). So, what are the possible mechanisms for this association?

• Some evidence suggesting short sleepers may have irregular eating patterns, predominantly with more energy dense snacking at night (4)
• Some evidence for having higher energy intake later in the day being associated with obesity and metabolic syndrome (6, 7)
• Possible differences in appetite related hormones (4)
• Increased energy intake simply because you are awake longer (4)
• Poor decision making when tired (8)
• Hedonic influence- greater neuronal activation in response to food stimuli particularly in areas associated with reward hence heightened motivation to seek reward (5)
• Patients with sleep disorders like sleep apnoea are more vulnerable to these effects (9)

How our nutrition affects how we sleep 

What we eat and how we eat can also affect how we are sleeping, so it is easy to see how someone may get into a cycle of poor diet and poor nutrition. This topic has more nuance, as the effects of food may depend on each individual, however there are some areas that have research. Firstly, the timing of meals may play a role, with late night meals before bedtime having negative effects on sleep, and some research suggesting that skipping breakfast and eating irregularly being strongly associated with poor sleep (10). The composition of macronutrients in the diet may also play a role, with evidence suggesting higher fat intakes, insufficient or excess protein and high glycaemic index all being linked to poor sleep (11, 12). On the contrary, a diet rich in seafood and vegetables has been linked to better sleep (12), with some evidence supporting the Mediterranean diet for sleep (11). Furthemore, long term inadequate nutrition may heighten inflammation in the body, which is linked to insomnia (6), therefore having a generally balanced diet may be protective.

What can I do? 

It is just not realistic for a lot of us to say we will definitely get 7-9 hours of good quality sleep every night, but we can certainly plan and prepare. Here are some tips to help nutrition in times of poor sleep:

• Be aware of how important sleep is, prioritise it. Can that task you’re doing at 11pm wait for tomorrow?
• Try out and utilise sleep apps if they work for you.
• Try not to time meals just before bed, and try making a food diary if you are struggling with sleep and nothing else is helping.
• Have healthy meals prepared in the fridge and freezer, so that you can grab and go or quickly heat them up. Hearty meals like a bolognese sauce or chicken pie may be good options over a salad, so if you are craving high energy and high fat foods, you can satisfy this craving without compromising on nutrition.

 

 

References

1. Shi L, Chen SJ, Ma MY, Bao YP, Han Y, Wang YM, et al. Sleep disturbances increase the risk of dementia: A systematic review and meta-analysis. Sleep Med Rev. 2018;40:4-16.
2. Baranwal N, Yu PK, Siegel NS. Sleep physiology, pathophysiology, and sleep hygiene. Progress in Cardiovascular Diseases. 2023;77:59-69.
3. Montaruli A, Castelli L, Mulè A, Scurati R, Esposito F, Galasso L, et al. Biological Rhythm and Chronotype: New Perspectives in Health. Biomolecules. 2021;11(4).
4. Dashti HS, Scheer FA, Jacques PF, Lamon-Fava S, Ordovás JM. Short sleep duration and dietary intake: epidemiologic evidence, mechanisms, and health implications. Adv Nutr. 2015;6(6):648-59.
5. Al Khatib HK, Harding SV, Darzi J, Pot GK. The effects of partial sleep deprivation on energy balance: a systematic review and meta-analysis. Eur J Clin Nutr. 2017;71(5):614-24.
6. Scoditti E, Garbarino S. Nutrition, Sleep, Circadian Rhythms, and Health Implications: “Come Together”. Nutrients. 2022;14(23).
7. Hermenegildo-López Y, Donat-Vargas C, Sandoval-Insausti H, Moreno-Franco B, Rodríguez-Ayala M, Rey-García J, et al. A Higher Intake of Energy at Dinner Is Associated with Incident Metabolic Syndrome: A Prospective Cohort Study in Older Adults. Nutrients. 2021;13(9).
8. Papatriantafyllou E, Efthymiou D, Zoumbaneas E, Popescu CA, Vassilopoulou E. Sleep Deprivation: Effects on Weight Loss and Weight Loss Maintenance. Nutrients. 2022;14(8).
9. Borel AL. Sleep Apnea and Sleep Habits: Relationships with Metabolic Syndrome. Nutrients. 2019;11(11).
10. Katagiri R, Asakura K, Kobayashi S, Suga H, Sasaki S, Diets tT-gSoWo, et al. Low Intake of Vegetables, High Intake of Confectionary, and Unhealthy Eating Habits are Associated with Poor Sleep Quality among Middle-aged Female Japanese Workers. Journal of Occupational Health. 2014;56(5):359-68.
11. Pot GK. Sleep and dietary habits in the urban environment: the role of chrono-nutrition. Proc Nutr Soc. 2018;77(3):189-98.
12. Sejbuk M, Mirończuk-Chodakowska I, Witkowska AM. Sleep Quality: A Narrative Review on Nutrition, Stimulants, and Physical Activity as Important Factors. Nutrients. 2022;14(9).