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.
Eating a healthy diet and regularly getting the sleep your body needs are not two separate rungs on a metaphorical ladder of wellness. They’re more like intertwining branches or vines that cross and separate but are undeniably linked.
Eating and digestion involve biological shifts — in glucose levels, blood flow, and hormone levels — that can affect our energy levels. So it should come as no surprise that our sleep can be impacted by what we eat and when we eat it. But what many people don’t realize is that how much we sleep influences what and how much we eat.
So let’s get right down to some FAQs:
In this article, we’ll answer each of those questions and more — adding details and context to show how diet and sleep fit into a larger wellness framework so that you feel and perform your best. We’ll explain why it can be difficult to go right to sleep after eating and share some simple guidelines for developing sleep-friendly eating habits. Because eating well and getting sufficient sleep are vital for having the energy you need to thrive day to day.
We’ve all been there: going overboard at a lunch buffet and arriving back at work feeling sluggish and sleepy. The technical term for the post-meal drowsiness some people call a “food coma” is postprandial somnolence.
Physiologically speaking, blood flow shifts and hormonal fluctuations may contribute to postprandial somnolence. While some scientists believe that a post-meal stupor 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.
If your post-meal sluggishness usually happens after lunch, the tiredness you’re experiencing might have less to do with eating and more to do with a normal circadian pattern.
Your circadian rhythm is an internal body clock that governs your sleep-wake patterns and energy fluctuations in roughly 24-hour cycles. An afternoon energy dip is a normal and predictable part of this daily rhythm. Although the exact timing varies from person to person and day to day, the RISE app will tell you when to expect your afternoon dip each day.
In his book Why We Sleep, Matthew Walker explains how poor sleep can lead to weight gain, starting at the hormonal level. Insufficient sleep can disrupt 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 can hamper functioning of the brain’s prefrontal cortex, making 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, making eating feel more pleasurable, which can increase cravings. Together with the other consequences of poor sleep — like lacking energy to exercise — sleep deprivation is the perfect storm 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 can quickly accumulate over weeks or months of insufficient sleep can also add up to more inches around your waistline.
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.
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.
The timing of your meals and snacks matters, too, because the digestive system is controlled by your circadian rhythm. The way we metabolize food varies at different times during each 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. Over time, this circadian misalignment can have adverse metabolic effects and increase the risk for Type 2 diabetes.
Because evening meals can disrupt your sleep patterns, making it more difficult to fall asleep and stay asleep, timing things right can make it easier to get the sleep your body needs. As a general rule, it’s best to finish large or heavy meals at least three hours before you go to bed. And for some people, taking meals within an 8- to 12-hour window — also called intermittent fasting or time-restricted eating — has been shown to further support the body’s natural digestive clock, which in turn can help you sleep better.
It’s easy to see how firing up your digestion just when the body is preparing to put its systems into "rest mode" for the night could make it hard to fall asleep and stay asleep. And when it comes to large meals, the closer you get to your bedtime, the more likely you’ll run into digestive issues that can keep you from falling asleep or wake you during the night.
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, acid reflux, or gastroesophageal reflux disease (GERD) — hardly a recipe for restful sleep.
What you eat at night also matters. In addition to avoiding caffeine and alcohol, steer clear of spicy, rich, fatty, and sugary meals before bedtime.
Although large late-night meals tend to be problematic, it is important to note that not everyone reacts to food before bed the same way. 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.
Some insulin-dependent diabetics may benefit from a small snack before they go to sleep because it can help balance their glucose levels and prevent hypoglycemia (low blood sugar) from disrupting their sleep.
In general, a balanced diet of fruits, vegetables, whole grains, nuts, and lean proteins is said to help with getting sufficient naturalistic sleep. If you’re looking to find key ingredients for sleep-friendly evening meals, choose foods rich in the following:
To maintain circadian alignment and prevent digestive discomfort from keeping you awake at night, 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 via your Energy Screen. It can also send you a late meal reminder that tells you the best time — based on your specific biology — to stop eating for the day. You’ll know the effort you put into fine-tuning your sleep and eating habits is paying off when you begin to feel and perform better each day.
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