It’s an age-old question when the tummy rumbles before bed— to eat or not to eat? And while some shy away from those nighttime munchies for fear of weight gain, studies suggest going to bed hungry can result in a loss of sleep and even cause the body to break down muscle mass overnightThe perilipin homologue, lipid storage droplet 2, regulates sleep homeostasis and prevents learning impairments following sleep loss. Thimgan, MS, Suzuki, Y., Seugnet, L., et al. Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri, United States of America. PLoS Biology, 2010 Aug 31;8(8). pii: e1000466Differential regulation of amino acid exchange and protein dynamics across splanchnic and skeletal muscle beds by insulin in healthy human subjects. Meek, SE, Persson, M., Ford GC, et al. Division of Endocrinology, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA. Diabetes, 1998 Dec; 47(12):1824-35..

Hunger and ZZZ’s — Why It Matters

Hunger pains have been shown to keep the brain mentally alert, so it can be more difficult to get a full night’s rest if hunger strikes during the night. Plus, not getting enough sleep can significantly lower metabolism and increase levels of the hormone ghrelin, which boosts appetite and might actually encourage weight gain ((Acute sleep deprivation reduces energy expenditure in healthy men.And over time, chronic sleep loss can weaken the immune system and possibly increase the risk for some forms of cancer, as well as diabetes.

Going to bed hungry doesn’t just mean less sleep— it could also be bad news for those trying to build muscle. Studies suggest falling asleep on an empty stomach can slow down the rate at which the body converts protein into muscle ((Responses of protein synthesis in different skeletal muscles to fasting and insulin in rats. Deprived of nutrients for long enough, the body can start to break down muscle for energy (also called a catabolic state). Looks like Ahhhnold got plenty of shuteye.

Eat and Sleep — The Answer/Debate

To avoid hunger pains at night, don’t skip meals during the day, since that can slow metabolism ((The effects of nocturnal life on endocrine circadian patterns in healthy adults. Studies also suggest eating small meals throughout the day causes the body to obtain energy from fat stores (instead of muscle) overnight ((Acute effects on metabolism and appetite profile of one meal difference in the lower range of meal frequency. If hunger does strike before bed, it’s still best to avoid an all-out fridge raid. Late-night eating has been linked to weight gain, and while some studies suggest consuming calories after 8 p.m. may increase the risk of obesity, others suggest calories have the same impact no matter what time they’re eaten.

It’s possible that study participants who ate late at night consumed the majority of their calories after sunset instead of spacing meals throughout the day. One thing is certain: Reaching for late-night treats high in calories can cause weight gain when daily calorie needs are exceeded. And going to bed on an overly full stomach might also lead to heartburn, which could prevent a good night’s sleep. Picking a smaller, lighter snack could be the best bet to sleep soundly without putting on extra pounds.