As it turns out, it’s not just what you eat that matters; when you eat can affect your sleep quality as well.
Studies show people with fluctuating schedules, like shift workers, who consume majority of their calories after a typical dinner report more sleep disturbances and lower sleep quality. However a 2015 review of these studies concluded that more research is needed to examine the effects of eating before bed, especially since most research is done with the goal of weight management.
When we take a closer look at eating before bed, from the effects your mealtimes have on sleep to what you eat before sleep, it becomes clear that eating before bed can become a problem if it’s a habit that doesn’t match your lifestyle or health goals.
“Food has chemical properties that in and of themselves can affect sleep and make an individual feel sleepy or more energetic,” says Dr. W. Chris Winter, neurologist, sleep specialist, and Sleep Advisor to Sleep.com. “Apart from the chemical effects of food, the timing of meal consumption can affect our circadian rhythms and impact sleep in that way, as well.”
You may want to avoid eating before bed if you:
- often feel an energy rush after eating
- have acid reflux, since lying down after eating can cause stomach acid to rise and cause heartburn
- need to wake up early in the morning, as regular nighttime eating can disrupt your sleep-wake schedule
- have inconsistent mealtimes (eat at a different time every day or for every time)
- tend to eat more at night
- are already at risk for cardiovascular disease, weight gain, or diabetes
Keep reading to learn about how the timing of meals and what you eat can affect your sleep and overall health.
How does eating before bed disrupt your sleep and circadian rhythm?
Though light is one of the strongest cues for our circadian rhythm — telling our bodies to ramp up or calm down — there are also other signals our brain relies on. Dropping temperatures can signal that it is time for relaxation. Eating, on the other hand, tells your brain it’s time to use energy and be awake. Having regular mealtimes, such as a predictable pattern for breakfast, lunch, and dinner, is suggested to have many health benefits, including an improved circadian rhythm.
Research also shows that eating at night, when there is no light out and your body expects rest, disrupts your metabolism and circadian rhythm. While one midnight meal isn’t likely to affect your circadian rhythm, regular nighttime eating can train or even reset your body clock to associate night with being alert and daytime with rest. The longer you maintain this routine, the stronger your body will associate off-hours time with alertness, which is why experts advise against making a habit of eating before bed.
According to a 2019 study, the hormone behind this circadian disruption is insulin. Researchers provided insulin to mice at times when they were typically at rest and noticed that the rodents experienced less distinction between night and day.
“We have known for some time that consistent meal timing and trying to avoid eating at night was a healthy endeavor,” Winter says. “As this study illustrates, eating inconsistently and eating late at night can affect the nature of our circadian rhythm and disrupt not only sleep, but many other processes involved in healthy living.”
Other processes affected by irregular or late-night eating habits may include:
- blood sugar processing — increasing your risk for type 2 diabetes
- heart health — increasing your risk for cardiovascular disease
- weight management — increasing your risk for weight gain
In addition to these physiological processes, there are other reasons to avoid eating late for better sleep: “Heavy meals prior to bed can create indigestion and other effects that lessen the quality of sleep,” Winter says.
How to schedule your meals for better sleep
Ideal mealtimes should be during the day, when you are active, and it is still light out. In fact, researchers looking into how the brain associates the timing of meals and sleep recommend encouraging earlier meals over earlier sleep periods because meal times are easier for people to control.
Fortunately for simple rules, there is also a simple strategy: Plan ahead.
1. Try to eat your meals the same time each day
“Eat your meals on a schedule,” Winter says. “When we eat consistently, our bodies begin to learn and anticipate what is coming, which is a far better metabolic model. Skipping meals and surprising the body with massive late-night meals high in glycemic content often wreaks havoc with our endocrine and insulin systems and disrupts sleep and health.”
There’s no one-size-fits-all meal schedule for everyone’s needs. Consistency is what’s key, and when it comes to sleep, the timing of dinner, in particular, is important — especially if you struggle with a condition like gastroesophageal reflux disease (GERD) or heartburn.
2. Aim to eat your largest meal earlier in the day
Studies show that eating earlier in the day helps the body digest, absorb, and metabolize better.
However, if you are unable to maintain a consistent mealtime each day or you feel stressed about having a strict eating schedule, you may want to consider time-restricted feeding (TRF). Time-restricted feeding is when you eat all your meals within a consistent 8- to 12-hour period.
In 2020, research has also found that TRF can help maintain your metabolic and behavioral circadian clock, even without calorie restriction, further suggesting that timing can indeed be everything.
3. Eat your last meal three hours before bedtime
To avoid issues like heartburn and indigestion, make sure you eat dinner at least three hours before bedtime.
Melatonin, which gets released at night when there is less light exposure, impacts insulin release and makes it harder for your body to process glucose. For this reason, researchers believe avoiding meals right before bed and as soon as you wake will lead to better health benefits.
4. Avoid skipping meals, if possible
Dinner’s not the only meal that matters when it comes to keeping your circadian rhythm in check, either. Experts say eating breakfast, lunch, and dinner at semi-regular intervals will likely keep the circadian rhythm ticking as it should and help prevent any unnecessary sleep disruptions.
5. Avoid caffeine and alcohol too close to bedtime
Avoiding caffeine might be a no-brainer, but it may surprise some that alcohol is also tricky for sleep. Even though alcohol has a sedative effect and can make you feel relaxed or sleepy, it also initially suppresses and then overproduces a natural stimulant called glutamine, which increases waking and light sleeping during the second half of the night. Alcohol also reduces rapid eye movement (REM) sleep, the most mentally restorative stage of sleep.
To reduce the risk of alcohol directly impact your sleep, it’s best to stop drinking at least four hours before bed
6. Consider skipping high-carbohydrate meals at night
In a 2016 review of diets and sleep, researchers found that high carbohydrate diets affect sleep quality by reducing how long it takes to sleep and slow wave sleep, while increasing REM sleep. High-fat diets appear to promote deep sleep, but also decrease time asleep and REM sleep, while increasing wake ups.
Not all the studies reviewed, however, tested the timing of foods. So unless you notice a measurable difference in your own experience, it may not be necessary to make dietary changes just yet. There are plenty of other tips to try first.
7. Don’t go to bed starving: It’s OK to have a snack
Late-night snacks before bed are actually OK, in moderation, provided that it’s a quality snack. The 2015 review mentioned above did find that for some people, going to bed with a snack can help with muscle recovery and metabolism.
In fact, research shows some people with type 1 diabetes may benefit from eating to avoid sleep disturbances from low blood sugar. However, snacks are not a solve for low blood sugar. It’s likely you may need to adjust your medication, so talk to a doctor if you’re frequently waking up at night.
Know when sleep disruptions are not food-related
All of these findings have significant implications for people like frequent travelers and shift workers, whose mealtimes may be irregular according to their circadian rhythm. And that’s good news — with a better understanding of how and why meal timing affects a good night’s sleep, experts can offer better solutions for maintaining a regular body clock, which is important for overall health.
However, Winter does offer a specific caveat for anyone who suspects that the timing of their meals may be the root cause of their sleep troubles.
“If you are struggling with insomnia, it’s doubtful that meal timing is playing that big of a role in your inability to sleep,” he says.
If you suspect your sleep problems are a result of an underlying health condition, it’s best to talk to a health professional. This is especially true if focusing on food, from meal times to ingredients, or implementing rules around your eating habits causes anxiety and stress that interfere with your day to day.