Have you ever found yourself wide awake in the middle of the night – watching television or surfing the web – while mindlessly snacking away on chips or sweets? Well, you’re not alone. A new study showed that people who don’t get enough sleep and are up late at night tend to add hundreds of calories to their daily diets.

Lack of adequate sleep is often combined with grazing on high calorie snacks during the wee hours. Researchers from the University of Pennsylvania studied people in a sleep lab and found that those who stayed awake until 4 am ate more than 550 extra calories than those who went to sleep much earlier.

During this sleep deprivation study, the 200 participants who were kept awake gained considerable weight compared to the people who were allowed to go to sleep at normal hours and get a good night’s rest.

The only difference between the people in the study was that the sleep-deprived group was only allowed to get 4 hours of sleep each night over the course of 5 days.

The author of this study found that those additional late-night calories “were higher in fat compared to the calories consumed at other times of day."(1) Instead of grabbing a piece of fruit to snack on, or preparing a small, healthy meal, late-night grazers are more likely to eat pre-packaged sweets and fatty snack foods. These foods are high in calories and low in nutritional value.

This link between lack of sleep and late-night snacking has been supported by other studies. Dr. Winter, of the Martha Jefferson Sleep Medicine Center in Virginia explains that “Late-night overeating is likely the result of hormonal changes that occur in people who are sleep-deprived.”(1)

People who are sleep deprived tend to have their ghrelin (a hormone that increases hunger) levels increase, while their leptin (a hormone that tells the brain you feel full) levels drop.

This type of late-night snacking on fatty or unhealthy foods is so common that it has been given the name “night-eating syndrome” (NES).

“Eating behaviour and circadian rhythm are proving to be important factors in the aetiology [cause] of obesity. The night-eating syndrome (NES) is characterized by increased late-night eating, insomnia, a depressed mood and distress.”(2)

Whether you are suffering from NES, going to bed too late, or simply not getting enough sleep at night, your body’s natural circadian rhythms and hormone levels can be disrupted – leaving you vulnerable to overeating and weight gain.

Researchers agree that the best way to avoid late-night eating is to get at least 8 hours of sleep every night. A full night’s rest keeps your circadian rhythm and hormones in balance, allowing your body to recharge. There’s a reason that caffeine and energy drinks are so popular – because the majority of us hit a midday or afternoon slump, long before our work day or other responsibilities have been completed.

Even people who do not actually have night-eating syndrome can find themselves awake in the middle of the night and unable to go back to sleep from time to time. Instead of picking up the remote and a tasty late night snack, try getting yourself a glass of water or decaffeinated tea and go back to bed.

If you are experiencing a lot of late-night eating combined with lack of sleep, moderate exercise for at least 30 minutes a day may help your body get on a better schedule. Eating nutritious, well balanced meals during the day may also limit your late-night snacking urges. 

Many people with NES skip breakfast entirely, consume many of their daily calories in the evening and late at night, and also suffer from insomnia. Severe cases of night-eating syndrome have been successfully treated with specific SSRI medications.(3)

If you are concerned you may be suffering from NES, you should speak with your physician about your symptoms and treatment options.

SOURCES: (1)Andrea Spaeth, doctoral candidate, psychology department, University of Pennsylvania, Philadelphia; Dr. W. Christopher Winter, medical director, Martha Jefferson Sleep Medicine Center, Charlottesville, Va.; July 2013 Sleep
(2)Gallant, A., Lundgren, J., & Drapeau, V. (2012). The night-eating syndrome and obesity. Obesity Reviews: An Official Journal Of The International Association For The Study Of Obesity, 13(6), 528-536.(3) Allison, K.C. & Tarves, E. (2011). Treatment of night-eating syndrome. Psychiatr Clin North Am, 34(4), 785-796. Online: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3222864/; Image courtesy of blackstock / FreeDigitalPhotos.net