Many people wrap up their day with a little snack before going to bed. That scoop of ice cream or nibble of cheese and crackers can feel so satisfying at the end of a long day. But your late night snack might affect the quality of your sleep. Take a look at the effects of late night snacking on both your digestion and your sleep.
Your body's circadian rhythms help govern your sleep/wake cycle, causing you to feel sleepy at night and wake up in the morning. You're probably aware that light affects those circadian rhythms, but you may not know your digestive system also follows similar rhythms, which can affect sleep habits and proper digestion.
Your digestive system expects to digest and metabolize food during the day, while you're working and need energy. At night, when you should be sleeping, your digestive system largely shuts down. If you eat late at night, however, you trigger your metabolism to get back to work. This throws your whole body out of sync and can result in increases in blood sugar and blood pressure, as well as weight gain and disruptions to your sleep cycle.
The more you eat before bedtime, the more likely you are to experience your digestive system still at work when you're trying to sleep. If your stomach is full, it's going to take a long time to digest the food — especially if your late night snack was high in fat or fiber.
In addition, the fact that you're lying down can cause your digestive processes to disrupt your sleep. While you're awake, your body position is largely upright. That means that gravity keeps the contents of your stomach headed in a downward direction.
As you eat, food moves from your mouth into your esophagus and then into your stomach. A valve called the lower esophageal sphincter opens to admit food into the stomach. If this valve doesn't close properly, your digestive juices can flow backward and enter the esophagus — which you experience as heartburn.
During the day, gravity helps keep that valve in check. At night, though, when you're lying down, gravity no longer assists you. If your stomach is busy producing digestive juices to process that late night snack, you're more likely to experience heartburn or acid reflux, which, of course, could keep you from sleeping comfortably.
If you experience heartburn more than twice a week, you may have GERD, or gastroesophageal reflux disease. In this case, that late night snacking is only going to make matters worse. Head to your doctor to see if you have an underlying condition that's exacerbating GERD.
Clearly, experiencing heartburn or indigestion at night may affect your sleep. It's hard to feel relaxed enough to drift off to sleep when your esophagus is burning or your stomach is churning away to digest that late night slice of pizza.
In fact, studies show that indigestion and GERD can make it more difficult for you to stay asleep once you've drifted off. You may not be consciously aware of the work your digestive system is doing at night. However, all that internal processing can wake you up in small ways and keep you from getting the deep sleep you need. As a result, you may wake up groggy, grouchy and feeling as if you didn't sleep (because you didn't).
Add more sleep issues to your personal mix if that late night snack included caffeine — and remember, chocolate contains caffeine. No wonder you don't feel rested in the morning.
Late night snacking can affect your sleep — but the flip turns out to be true as well. Sleep deprivation can cause you to crave late night snacks. A 2019 study looked at the effect of sleep restriction on eating and digestion. Participants who were limited to five hours of sleep per night demonstrated a greater desire to eat late in the day, possibly because their circadian rhythms were disrupted. With a greater calorie intake late at night, when the body's metabolism is slowing down in preparation for sleep, these participants also gained more weight than the control group.
In addition, the sleep-deprived late night eaters showed decreased insulin sensitivity, indicating that their metabolisms were starting to show negative effects of sleep deprivation. This study added to the evidence that sleep deprivation is a risk factor for diabetes as well as obesity. The bottom line: Late night snacking and sleep problems go hand in hand in several ways.
If you find yourself struggling with the desire to eat late at night, there are a few things you can do to set your body up for a good night's sleep:
© 2021 American Sleep Association.