For many of us, a satisfying little bedtime snack is an essential part of our evening ritual. Having some cheese and crackers or a bowl of cereal before bed certainly beats trying to sleep with a rumbling belly. And of course there’s also something to be said for ending a weekend night out with that 1 a.m. slice, or ending a lousy day with a big ol’ bowl of rocky road.

At the same time, you may have heard advice warning against eating at night because it’s bad for your digestion, sleep, or weight. Well, before you even think about giving up your beloved bedtime routine (or spontaneous midnight picnic), let’s take a look at what effects that eating before bed can actually have on your health.

Eating before bed and digestion

While our bodies are indeed perfectly capable of doing two things at once—sleeping and digesting, in this case—hitting the sack right after feasting is not ideal for many people because of the way the gastrointestinal (GI) tract is set up.

Between the stomach and the esophagus (the tube that carries food from your mouth to your stomach) is a muscular valve called the lower esophageal sphincter, according to the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK). Sometimes this valve remains open, allowing the contents of the stomach and digestive juices to flow back up into the esophagus and cause irritation, Scott Gabbard, M.D., a gastroenterologist at Cleveland Clinic, tells SELF. That unpleasant burning sensation (and sometimes taste) in your throat and/or chest is known as gastroesophageal reflux (i.e. acid reflux or heartburn).

Heartburn can be triggered by a few things, including eating and then lying down, according to the Mayo Clinic. In other words exactly the scenario when you eat before bed. When you lie horizontally with a full stomach “[you] lose the effect of gravity that helps to keep the contents of the stomach down,” Dr. Gabbard explains, which causes this backflow. Everyone can get heartburn once in a while, but if you have it more than twice a week you might have what’s called gastroesophageal reflux disease (GERD), according to the U.S. National Library of Medicine.

Another risk of nighttime eating is dyspepsia, more commonly known as indigestion or an upset stomach. This is a set of symptoms—like stomach pain, nausea, getting uncomfortably full or full very quickly, and upper abdomen bloating or burning—that can commonly be triggered by eating quickly; overeating; eating food that is fatty, greasy, or spicy; or drinking too many caffeinated, alcoholic, or carbonated beverages, according to the NIDDK.

Just as with heartburn, mild or occasional indigestion is usually nothing to worry about. If it lasts longer than two weeks or is accompanied by other symptoms, it’s a good idea to see a doctor who can help you figure out if you have an underlying digestive issue such as gastritis, or functional dyspepsia, which is chronic and has no underlying cause, according to the National Institute for Diabetes and Digestive and Kidney Diseases (NIDDK).

But whether you have occasional or chronic acid reflux or indigestion, “eating a large meal before going to bed could worsen the existing symptoms,” Dr. Gabbard says. That’s why the NIDDK advises avoiding late-night eating and waiting two or three hours to lie down after eating.
Also keep in mind the size and contents of your nighttime snack or meal if you experience either of these issues. Bigger meals take longer to digest than light snacks, Dr. Gabbard explains—and the fuller your stomach is the longer it takes to break it all down, and the more likely it is you will experience GERD or dyspepsia. Some kinds of foods also take longer to digest than others, like anything high in fibre or fat. Spicy and acidic foods can also aggravate acid reflux and indigestion, per the NIDDK.

So in general, for your tummy’s sake the ideal nighttime snack is one that’s smaller, milder, lower in fat and fiber, and eaten a couple hours before bed. Of course, if making these changes isn’t helping, see your doctor because there are other lifestyle modifications and medications available.

Eating before bed and sleep quality

If you regularly eat close to bedtime and have trouble getting a good night’s sleep, it’s definitely worth considering whether there’s a connection there.

The main concern actually goes right back to acid reflux and indigestion, which can make it hard to fall asleep, Dr. Gabbard points out, as can simply feeling too full. But GERD and indigestion can also make it harder to stay asleep, Rajkumar Dasgupta, M.D., a clinician and associate professor at Keck Medicine of USC’s division of pulmonary, critical care, and sleep medicine, tells SELF. Both issues can cause small arousals that you might not remember, but can prevent you from getting into deeper phases of sleep and leaving you under-rested and groggy in the morning, Dr. Dasgupta says.

At the same time, if you’re not having any issues with sleeping (or reflux or indigestion), there’s really no reason to change up your nighttime eating habits. In fact a solid bedtime routine can help signal to your body and mind—which have been going all day—that it’s time to slow down and rest now, Dr. Dasgupta says. And just as with drinking tea, taking a bath, or reading a book, enjoying a snack may help you unwind and prepare for a good night’s sleep. Plus lying there with a rumbling tummy can occupy your mind and make it hard for your body to relax, Dr. Dasgupta says. So if you need a bedtime snack to stave off late-night hunger, then go for it.

Also keep in mind that there are approximately 7,000 things that can affect your ability to fall and stay asleep besides nighttime eating—caffeine intake, exercise, sleep habits, anxiety, sleep disorders. So instead of jumping to any conclusions, Dr. Dasgupta recommends keeping a sleep journal tracking all of these things for a couple weeks to see if there’s any correlation. If you notice that you consistently get less sleep or feel less well-rested in the morning after eating right before bed, then try shrinking or skipping your bedtime snack and see what happens.

Eating before bed and weight

Many of us associate nighttime eating with weight gain. In fact you’ve probably seen weight-loss tips about not eating past a certain hour. Plus with the popularity of intermittent fasting (that involves only eating during a set window, like 10 a.m. to 6 p.m.), you might wonder if there’s something to that.

Long story short? There could be a connection there, but we don’t actually know enough about it yet to say much of anything. There is some research indicating an association between nighttime eating, weight, and metabolic function, Kelly C. Allison, Ph.D., an associate professor of Psychology in Psychiatry at the Perelman School of Medicine at the University of Pennsylvania and director of the Center for Weight and Eating Disorders, tells SELF.

A literature review published in Physiology & Behavior in 2018 coauthored by Allison concluded that while the body of research is flawed and incomplete, some findings from small studies suggest that the timing of eating impacts weight and metabolic function—specifically, with regular nighttime eating potentially contributing to metabolic dysfunction and daytime eating having either no or beneficial effects.

One theory is that shifting calorie consumption to later in the day could alter the body’s circadian rhythm, which helps regulate metabolism. “Our bodies are set up to be awake and eating and moving during the day, and sleeping and fasting overnight,” says Alison. But this is still just a theory. The authors acknowledge the need for much more research, including larger and better-controlled studies conducted on diverse populations over longer periods of time, before we can make any generalisations about a link. (Alison recently wrapped up a pilot study on the topic.)

What we do know for sure? Even if there is a connection here, Alison says, it’s just one piece of the complex puzzle of your health, metabolism, and weight. “It’s still largely about the nutritional value and amount of food you’re eating, no matter the time of day,” Alison says.

Something else we can say with 100 percent confidence: Whether or not your weight ticks up or down based on your nighttime eating habits is not necessarily something to fret about. Weight is not the sole (or even most important) indicator of your health.

So at the end of the day—literally—you can probably snack before bed and sleep easy. If you are having a problem with heartburn, indigestion, or sleep quality, then it’s worth sticking to these general guidelines: Make it a smaller snack or meal; skip foods that are extremely fibrey, fatty, spicy, or acidic; and time it at least a couple hours before you get into bed. And if your symptoms continue, make an appointment with your GP.