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Sleeping After Eating: Why You Feel Tired + How Long To Wait?

Sleeping and eating are more intertwined than you realize. Understand why you feel sleepy after a meal, how long you should wait to sleep after eating, and why.
Published
2021-09-22
Updated
2022-07-18
12 MINS
Woman eating before going to sleep: sleeping after eating

Some experts will tell you that it’s normal to feel sleepy after eating. Others may warn that eating a big meal before bed will disrupt your sleep. How can both of these things be true? It has to do with the unique relationship between food and sleep.

There’s a growing body of research that suggests the timing of our meals play a key role in keeping sleep debt low and helping us stay in circadian alignment. Sleep debt is the amount of sleep you’ve missed in the past 14 days relative to your sleep need (the genetically determined amount of sleep your body needs). Circadian alignment refers to keeping your internal body clocks steady and in sync through vital circadian cues like consistent meal times (more on that later).

But it’s not just when you eat that matters; what and how much you eat also influence your running sleep debt and body clock. Food choices (to eat a doughnut or a salad?), the nutritional composition (how much fats, proteins, and carbs should you aim for?), meal size (how many calories are you taking in?), and even the accompanying beverage either help or hinder sleep.

Ahead, we explain how long you should wait to sleep after eating and the reasons behind it. We’ll also share why you may feel sleepy after a meal and what you can do to minimize the so-called food coma. It’s all in the name of better sleep tonight for better energy the next day.

How Long Should I Wait to Sleep After Eating?

When it comes to your last meal of the day, the science is clear that you should try to eat 2-3 hours before you sleep. ​​Firing up your digestion just when the body is preparing to put its systems into "rest mode" for the night makes it hard to fall asleep and stay asleep.

Why You Shouldn’t Sleep After Eating

RISE app screenshot showing when to have your last large meal of the day.
Add the “Avoid Late Meals” habit to your Energy Schedule in the RISE app to remind yourself to stop eating three hours before bed.

For starters, dozing off right after a large meal will lead to digestive issues. That’s because an upright position — whether sitting or standing — is better for digestion in general. Lying down with a full stomach too soon after a meal can cause gastrointestinal discomfort and may worsen symptoms of heartburn, indigestion, or gastroesophageal reflux disease (GERD) — hardly a recipe for restful sleep. Sleeping after eating also lowers your arousal threshold (how likely it is something wakes you), increasing sleep fragmentation (how often you wake up during the night). This inevitably makes it difficult to meet your sleep need. 

The time you eat in the evening should also be consistent from day to day. That’s why we created the “Avoid Late Meals” habit in the RISE app, which you can add to your Energy Schedule. You will receive an in-app reminder to stop eating three hours before your Melatonin Window. This is the period in which your body’s melatonin production peaks, making it the ideal time to go to bed.

Although large late-night meals tend to be problematic for the reasons above, it is important to note that not everyone reacts to food before bed the same way. Some may benefit from a small snack before they go to sleep because it can help balance glucose levels and prevent hypoglycemia (low blood sugar) from disrupting sleep.

If you find you often wake up with hunger pangs in the middle of the night, losing sleep in the process, it’s not a bad idea to experiment with eating a light snack closer to your bedtime. But we recommend keeping the meal or snack under 600 calories. And steer clear of simple carbs like baked goods, fruit juices, or sugary cereals.

It’s Not Just Your Last Meal of the Day That Matters

It’s not just the timing of your last meal that impacts circadian alignment but all meals. That’s because food is a zeitgeber (a circadian cue). In situations like night shifts, it’s recommended that you don’t eat outside of your natural sleep-wake cycle even though you may be awake during that time. Doing so invites circadian misalignment, which a study published in October 2021 cautioned leads to weight gain, increased blood glucose levels, and fattier livers. The good news is that realigning your body clocks by practicing consistent meal times can lower your odds of these metabolic health risks.

For some people, taking meals within an 8- to 12-hour window — also called intermittent fasting (IF) or time-restricted eating (TRE) — has been shown to further support the body’s natural digestive clock, which in turn can help you sleep better. Eating during a specified time frame helps keep your meal timings consistent from day to day. Also, IF can act as a buffer before bed to avoid falling into the unhealthy habit of eating too late at night. Bonus: These eating patterns can enhance your circadian health, brain health, and cardiometabolic health (blood pressure, blood glucose, cholesterol, body weight, and heart disease). For context, recent scientific insights published in July 2022 found that only about 7% of the adults in America have good cardiometabolic health. 

How Does Sleep Affect Eating, and Vice Versa?

How long you should wait to sleep after eating is probably the question that’s top of mind. But it’s worth considering, for the sake of your sleep and daily energy, the full bidirectional impact of sleep and meals in general.

How Does Sleep Affect Your Meals?

In his book Why We Sleep, Matthew Walker explains how poor sleep can lead to weight gain, starting at the hormonal level. Based on a new study published in 2022, scientists discovered that sleeping for only four hours a night increased subcutaneous belly fat by 9% and abdominal visceral fat by 11%, compared to those who slept 9 hours a night. (You can read more about the inescapable link between sleep debt and weight gain here.)

Insufficient sleep disrupts normal levels of appetite-controlling hormones in the body. When you’re sleep deprived, the hunger hormone ghrelin rises, and the satiety hormone leptin falls. The result? You eat more and feel less full. To make matters worse, lack of sleep hampers functioning of the brain’s prefrontal cortex. This makes impulse control more difficult and those leftover doughnuts harder to resist.

At the same time, endocannabinoids, chemical messengers that act on the brain's pleasure receptors, flood the body. Eating feels more pleasurable, which can increase cravings. Insufficient sleep affects not just how much you eat but also the foods you choose. You’re more likely to crave salty, carb-heavy, and sugary foods when you don’t get enough sleep. Together with the other consequences of poor sleep — like lacking energy to exercise — sleep deprivation is a recipe for weight gain. 

A 2016 study published in the European Journal of Clinical Nutrition showed that restricting sleep to five hours led people to eat up to 385 extra calories the following day. The excess calories that quickly accumulate over weeks or months of insufficient sleep also add up to more inches around your waistline. (Check out how to lose the extra belly fat here.)

The study included data about the question of "extra" calories a person may burn by being awake longer, and the amount turned out to be trivial. If you deprive a person of sleep for 24 consecutive hours, they will only burn about 147 extra calories, compared to a 24-hour period that includes eight hours of sleep. That’s because sleep is a metabolically active state — for the brain and the body.

The good news is that you can learn how to lose weight without exercising, just by getting your sleep right.

How Does Eating Affect Sleep?

On the other side of the coin, eating affects your sleep, too.

To reiterate, the timing of your meals and snacks matters because the digestive system is controlled by your circadian rhythm. The way we metabolize food varies at different times during a roughly 24-hour cycle. And because food intake is a circadian cue, the timing of meals can shift sleep-wake times and frequent snacking can disrupt them, potentially leading to lack of energy and weight gain.

Case in point: In December 2021, researchers found that eating at night worsens glucose intolerance and circadian misalignment, increasing the risk for Type 2 diabetes. Restricting meals to daytime stopped this from happening, even when participants stayed up at night.

Certain foods like caffeine and alcohol also delay and fragment sleep. The end result is that you’re less likely to meet your sleep need, racking up sleep debt that sets off a vicious cycle of weight gain, obesity, and poorer overall health, as previously mentioned.

So, what should you eat for better sleep? In general, a balanced diet of fruits, vegetables, whole grains, nuts, and lean proteins is said to help with getting sufficient naturalistic sleep. A recent literature review in June 2022 shows that a healthy diet is associated with better perceived sleep quality.

Certain types of foods and micronutrients may promote sleep, such as:

  • Tryptophan is a sleep-promoting amino acid that’s converted to serotonin and then to melatonin in the brain. It’s found in turkey, chicken, eggs, spinach, chickpeas, milk, nuts, dried dates, and oats.
  • Melatonin, a sleep-inducing hormone produced by our bodies, is also found in a variety of foods including eggs, fish, nuts, brown mushrooms, seeds, tart cherries, corn, asparagus, tomatoes, pomegranate, olives, grapes, and broccoli.
  • Magnesium is a powerful mineral and a natural relaxant that can suppress adrenaline production. Because magnesium deficiency can cause sleep problems, look for magnesium-rich foods like dark leafy greens, nuts, seeds, fish, soybeans, avocados, and bananas.
  • Fiber is an indigestible carbohydrate that’s good for digestion, sleep, and overall health. To reap its benefits, eat plenty of beans, broccoli, berries, avocados, apples, nuts, and whole grains.

If you need help creating sleep-friendly meals, especially in the few hours before bedtime, speak with a licensed healthcare professional, like a dietitian or nutritionist.

Why Do I Feel Sleepy After a Big Meal?

RISE app screenshot showing your energy peak and dip times.
RISE shows your daily energy peaks and dips on your Energy Schedule to help you preempt sleepiness after eating.

You might also be wondering about another sleep and eating dynamic — the feeling of sleepiness after a meal, particularly lunch. What’s commonly known as “food coma” is technically called “postprandial somnolence” or “postprandial fatigue.”

Physiologically speaking, blood flow shifts and hormonal fluctuations may contribute to post-meal sleepiness. While some scientists believe that this is caused by a shift in blood flow to the small intestine — and away from the brain — others point to the hormones involved in eating and digestion.

Cholecystokinin, a peptide hormone released when we eat, can induce feelings of sleepiness. At the same time, wakefulness is suppressed because higher blood sugar levels inhibit the production of orexins, neuropeptides that promote the release of excitatory hormones.

Meanwhile, certain food sensitivities and allergies like gluten intolerance can lead to symptoms of brain fog and fatigue that make you feel sleepy after eating. Other medical conditions like diabetes, hypoglycemia, anemia, and hypothyroidism (an underactive thyroid gland) can also incite post-meal drowsiness.

That being said, it could be that it’s not your food that’s to blame, but rather, the mid-afternoon dip in your circadian alerting signals. Also called the “Afternoon Dip,” which you can view on your Energy Schedule in the RISE app, it happens regardless of whether you ate or not, and certainly exacerbated by sleep debt. Of course, a heavy meal of highly processed carbs will intensify this post-meal fatigue by spiking your blood glucose levels. The resulting sugar crash then dampens your energy levels, worsening tiredness.

Your best bets for making the most of your natural energy dip is to engage in dip-friendly activities — not sure what qualifies as dip-friendly? We’ve got some great examples in our post on “How to wake yourself up when tired.” On top of that, keep your sleep debt low and eat foods that sustain level energy rather than zap you of it (think complex carbs like whole wheat pasta instead of sugary, processed foods like doughnuts).

Make Your Eating Habits More Sleep-Friendly With RISE

To maintain circadian alignment and prevent digestive discomfort from keeping you awake at night contributing to sleep debt, avoid big meals in the three hours before bed. And because consistency is an important part of supporting a robust circadian rhythm, try to stick to a regular eating schedule to help optimize your sleep and daytime energy.

The RISE app automatically maps your circadian rhythm (as seen on your Energy Screen). This way, you’ll know the best time for you to have your last meal. 

Note, while the timing and composition of your meals is an important aspect of good sleep hygiene, it’s only a part of it.

To meet your sleep need for better energy, follow science-backed behaviors 24/7 to maximize your days and nights. Well-timed light exposure and temperature control are key sleep hygiene best practices in addition to the optimal and consistent timing of meals.

If you need help in improving your sleep hygiene, RISE’s 20+ science-backed habits and our step-by-step Sleep Guide will guide you through all of it to reach your full energy potential.

Get more of your questions about eating, sleep, and daily energy answered:

Summary FAQs

Is it bad to sleep after eating?

It’s not recommended to sleep after eating because you will likely experience digestive issues like indigestion, heartburn, and acid reflux that disrupt your sleep. Also, sleeping after eating lowers your arousal threshold and fragments your sleep, making it harder to meet your sleep need, which affects your next-day energy levels.

What happens if you sleep after eating?

If you sleep directly after eating, you’ll probably encounter indigestion, heartburn, and other digestive problems that disrupt nighttime sleep. You also increase your risk of unhealthy weight gain, obesity, and poor health over time.

How long should I wait to sleep after eating?

As a general rule of thumb, you should wait 2-3 hours to sleep after eating.

Can I sleep 1 hour after eating?

Sleeping one hour after eating doesn’t give your body enough time to digest the food, inciting digestive problems like heartburn and acid reflux. It’s recommended to wait at least 2-3 hours before you go to bed after a meal.

How do I stop feeling sleepy after eating?

Feeling sleepy after eating your lunch is in large part due to the afternoon energy dip, which is a normal fluctuation of your circadian rhythm, and happens to everyone. That said, there are two things you can do to minimize the post-meal drowsiness: keep your sleep debt low and avoid highly processed, carb-rich foods.

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Rise is the only app that unlocks the real-world benefits of better sleep.

Instead of just promising a better night, we use 100 years of sleep science to help you pay down sleep debt and take advantage of your circadian rhythm to be your best.

Over the past decade, we've helped professional athletes, startups, and Fortune 500s improve their sleep to measurably win more in the real-world scenarios that matter most.

Rise Science is backed by True Ventures, Freestyle Capital, and High Alpha; investors behind category winners Fitbit, Peloton, and Salesforce Marketing Cloud.
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