We all need to sleep and we all need to eat. But these two essential behaviors are tightly linked — and they can mess with each other.
You’ve probably experienced the dreaded post-lunch food coma, the feeling of being bloated in bed after a late-night dinner, or being extra hungry after a night of no sleep. But why do all of these things happen?
Below, we’ll dive into your questions about sleeping, eating, and energy. Plus, we’ll share how the RISE app can help you master meal timings and sleep to get more energy.
“Feeling sleepy after eating is normal, especially if you’ve just had a heavy, carb-rich meal. But you’ll feel more tired than usual just after lunch, during your natural afternoon dip in energy, and if you’re sleep deprived,” says Dr. Chester Wu, who is double board certified in Psychiatry and Sleep Medicine, and provides sleep medicine services, medication management, and psychotherapy to adults at his private sleep medicine and psychiatry practice.
It’s not entirely clear why we feel sleepy after eating, but it could be due to a blood sugar crash, a change in hormones, sleep deprivation, or your energy levels naturally falling as part of your circadian rhythm.
Feeling sleepy after eating is known as “postprandial somnolence” or “postprandial fatigue.” You might also know the feeling as a “food coma.”
Let’s dive into the theories behind post-meal sleepiness in more detail.
After eating, blood flow may shift from our brains to our small intestines, making us sleepy. And hormones like cholecystokinin, which are released when we eat, may also contribute to our drowsiness. High blood sugar levels can block certain neurons in our brains that make us feel awake, and the following sugar crash can certainly leave you feeling low on energy.
A high-calorie meal or high-carb meal can also make you feel sleepier than usual. And if you’ve had an alcoholic drink with your meal, this could be to blame for your drowsiness.
Food sensitivities and allergies, like gluten intolerance, can also lead to sleepiness and brain fog. And medical conditions like diabetes, hypoglycemia, anemia, and hypothyroidism (underactive thyroid) can also make you feel tired after a meal. You may also feel sleepy after not eating enough, like if you’re on Ozempic and cutting your calories.
But your post-meal tiredness may not have anything to do with eating at all. Our energy levels naturally fluctuate over the course of the day as part of our circadian rhythm, or body clock. There’s a natural dip in energy in the afternoon, which often comes after typical lunch times, and in the evening, often after dinner.
Curious about what your circadian rhythm looks like? RISE can predict the timing of your circadian rhythm each day, so you can see when your energy levels are expected to dip in the afternoon and late evening.
And if you’ve been missing out on sleep recently, you’ll have high sleep debt. Sleep debt is the amount of sleep you owe your body. If you’ve got high sleep debt, that afternoon dip in energy is going to feel much worse, and you’ll have lower energy levels all day long — no matter what and when you eat.
To see if sleep debt is to blame, RISE can work out how much sleep debt you have. We recommend keeping it below five hours to maximize your energy levels.
In summary, you may feel sleepy after eating because of:
You may feel tired after lunch because you’re experiencing a sugar crash, you had a big meal high in calories or carbs, or you have food sensitivities or allergies. Afternoon sleepiness is also a natural part of your circadian rhythm, and it’ll feel worse if you’ve got a lot of sleep debt.
Boost your energy after lunch by paying back sleep debt (by sleeping more at night or taking naps) and having a light and healthy lunch.
You may not be able to avoid the afternoon slump altogether, though. Many people will feel sleepy in the afternoon, no matter what they’ve eaten or even if they've skipped lunch, due to the natural dip in energy that comes with your circadian rhythm.
This usually happens around 1 p.m. to 3 p.m., but it can happen earlier for early birds and later for night owls. So your afternoon dip in energy may hit you right after lunch.
If this is the case, work with your circadian rhythm, rather than against it, and use this time to take a break, do easy tasks, or take a nap. Check RISE to see when this dip in energy will be to plan your day.
We’ve covered more on how to beat the afternoon slump here, including the best lunches to go for to keep your energy levels higher.
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Some types of foods can make you feel sleepy. But rather than individual foods, you’re more likely to feel tired from large meals or meals that are high in sugar or carbs.
These foods can cause sleepiness:
We’ve covered more on what gives you energy here, including the foods that can increase your energy levels.
To stop feeling tired after eating, keep your sleep debt low, stay in sync with your circadian rhythm, and eat light and healthy meals that aren’t too high in carbs or sugar.
Here’s more on how to make that happen:
Already battling tiredness after a meal? We’ve covered how to wake yourself up here.
Expert tip: It’s easy to blame meals for your tiredness, but it can very easily be your sleep — or lack of it. In fact, you may need more sleep than you think.
The amount of sleep you need each night is called your sleep need, and this number is different for each of us.
We looked at the sleep needs of 1.95 million RISE users aged 24 and up and found the median was eight hours. But 48% of users need eight hours or more sleep a night. And some even need 11 hours 30 minutes!
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You may be feeling extra sleepy after meals because you’re not meeting your sleep need.
To find out, RISE can work out how much sleep you need based on a year’s worth of phone use behavior and proprietary sleep-science-based models.
Yes, it’s normal to feel sleepy after eating to some extent. More research needs to be done, but it’s probably caused by high sleep debt, a natural drop in energy as part of your circadian rhythm, or a high-carb or high-calorie meal. You may also be tired due to multiple factors, or factors that are difficult to diagnose, such as a medical condition or sleep disorder. So finding the underlying cause, or causes, of your sleepiness after eating can be tricky.
Try lowering your sleep debt, getting in sync with your circadian rhythm, and eating light and healthy meals to feel less tired after eating.
If you have uncontrollable tiredness after a meal, reach out to your healthcare provider. They can run tests for underlying medical conditions or allergies that may be to blame.
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It’s bad to eat before sleeping as eating close to bedtime can keep you up or wake you up in the night, causing sleep deprivation.
Eating and then laying down too soon can cause digestive issues, like acid reflux, which can keep you awake. And eating lowers your arousal threshold, which is how easily you can be woken up from sleep. So even if you can drift off soon after a meal, you may find yourself waking up in the middle of the night.
Science backs this up. Research shows high-calorie food intake about 30 to 60 minutes before bed can increase how long it takes you to fall asleep. And a 2021 study found eating an hour or less before bed makes it more likely you’ll wake up in the night.
Eating can also change the timing of your circadian rhythm. When your circadian rhythm is out of whack, from eating late at night or during the night, you may experience low energy, trouble sleeping, and health issues like diabetes and obesity.
Eating before bed can also lead to weight gain, and all of the adverse health effects that come with it.
You should wait two to three hours to sleep after eating. This should give your digestive system enough time to get to work so that gastrointestinal issues don’t keep you awake.
Avoiding meals in the late evening can also help to keep your circadian rhythm in check, which will benefit your sleep, energy levels, and overall health and well-being.
For more on the science behind meal timing, we’ve covered what time you should stop eating before bed here.
And to help you master your meal times, RISE can tell you when to have your final meal each day based on the timing of your circadian rhythm.
Sleeping after eating can affect weight loss. Here’s why:
To maximize your weight loss efforts, try to be finished with dinner two to three hours before bed for the best sleep.
Eating dinner earlier than this may help you lose more weight. Research from 2021 suggests intermittent fasting or time-restricted eating (when you eat your meals within a set window of time and perhaps cut your calories too) can help promote weight loss, improve insulin resistance, and decrease blood pressure.
And a 2023 study found time-restricted eating was linked to getting more overall sleep and sleeping earlier.
But more research needs to be done. We’ve covered more on intermittent fasting and time-restricted eating here.
Expert tip: Meal timing is important, but getting enough sleep overall is key for losing weight and keeping it off. A 2023 study found those with short sleep durations were more likely to regain weight in the year after they’d lost it compared to those who got enough sleep.
Trying to lose weight? We’ve covered more on what time you should stop eating to lose weight here.
Ideally, you would avoid eating altogether two to three hours before bed. But if you need to eat close to bedtime, opt for a light healthy meal or snack. Opt for fresh fruit, peanut butter, cottage cheese, or Greek yogurt.
It’s best to not eat before bed as it can keep you up or wake you up in the night. But some people, like those with type 1 diabetes, may benefit from a small snack before they go to sleep because it can help to prevent hypoglycemia (low blood sugar) from disrupting sleep.
And if you find hunger pangs wake you up in the night, try eating more during the day, or eating a small light snack before bed. Make sure your diet has enough fruits, veggies, and complex carbs to keep you fuller for longer.
Ideally, you would finish your last meal of the day two to three hours before bed. But if you do need to eat before bed, avoid anything that’s high in carbs or sugar, and anything that’s fatty, fried, or spicy. High-calorie meals can also mess with sleep, so try having a smaller meal or snack instead.
Beyond food before bed, think about what drinks you’re having, too. Be sure to avoid caffeine or alcohol, both of which can make it harder to fall and stay asleep. And avoid drinking too much water before bed, as this can lead to middle-of-the-night bathroom trips.
The best position to sleep in after eating would be to not sleep at all. Instead, remain sitting or standing up and head to bed in two to three hours. But if you have had a late-night meal and need to sleep, try sleeping on your left. A 2022 study found sleeping on your left can reduce acid reflux and symptoms of gastroesophageal reflux disease (GERD).
We’ve covered the best side to sleep on for digestion here. And for trying to lose weight, we share the best side sleeping positions to lose weight here. (Spoiler: there’s no magic position, the key is to get enough sleep overall).
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Not getting enough sleep can cause you to eat more and eat unhealthier.
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 impairs your 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 (often foods that, ironically, make you more sleepy) when you don’t get enough sleep.
And a 2016 study showed that restricting sleep to five hours led people to eat up to 385 extra calories the following day.
Together with the other consequences of poor sleep — like lacking the energy to exercise — sleep deprivation is a recipe for weight gain.
A study published in 2022 found that sleeping for only four hours a night increased subcutaneous belly fat (the fat under the skin you can see) by 9% and abdominal visceral fat (the fat around your organs) by 11%, compared to those who slept nine hours a night.
The good news is that you can learn how to lose weight without exercising, just by getting your sleep right.
Check RISE to see how much sleep debt you have. Got a lot? This could be affecting your hunger levels, food cravings, and weight loss efforts.
Both what you eat and when you eat affect your sleep. Healthy meals at regular times that are not too close to bedtime can help you get the sleep you need. But unhealthy meals at night or late at night can make it harder to get enough sleep.
Here’s what science has to say on that.
A 2022 study found “diets rich in fiber, fruits, vegetables, and anti-inflammatory nutrients and lower in saturated fat (eg, Mediterranean diet) were associated with better sleep quality.” Diets higher in protein, healthy fats, and complex carbs were also linked to better sleep quality. (Although there’s no set definition for sleep quality).
Research also shows eating more fiber is linked to getting more deep sleep. And getting more of your energy from saturated fat is linked to less deep sleep. Plus, getting more energy from sugar and simple carbs is linked with waking up more in the middle of the night.
As we’ve already shared, you don’t want to eat too close to bedtime as this can keep you up or cause you to wake up in the night. You also want to avoid eating during the night, if possible.
Research from 2021 found that eating at night worsens glucose intolerance and can cause you to get out of sync with your circadian rhythm, which can increase your risk of type 2 diabetes. Eating during the day, even if you have to be awake at night for night shifts, can stop this from happening.
Feeling sleepy after eating is normal. But you will feel more tired if you’ve got high sleep debt, you’re out of sync with your circadian rhythm, or you’ve had a high-carb or high-calorie meal.
The RISE app can reduce your post-meal drowsiness. The app works out how much sleep you need and how much sleep debt you have, so you can work to lower it. RISE also predicts your circadian rhythm each day, so you can get in sync with it and see when your natural dips in energy will be each day.
Lowering your sleep debt and getting in sync with your circadian rhythm will boost your energy levels, both after meals and throughout the day as a whole.
And to help you get a good night’s sleep, RISE can tell you when to finish up your final meal by each day.
It doesn’t take long to see the effects — 80% of RISE users feel more energy within five days.
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.
It can be bad to sleep after eating. Sleeping 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 two to three hours before you go to bed after a meal.
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 two to three hours before you go to bed after a meal.
You should wait two to three hours to sleep after eating. That should give your body enough time to start digesting food, so issues like acid reflux and bloating don’t keep you awake.
You may fall asleep after eating due to being sleep deprived, experiencing a natural dip in energy as part of your circadian rhythm (this happens in the afternoon and late evening), or because you’ve had a high-calorie, sugary, or high-carb meal.
Stop feeling sleepy after eating by eating lighter and healthier meals with more protein and less sugar and simple carbs. Lower your sleep debt and get in sync with your circadian rhythm to feel more energy after meals and overall.
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