Why You Feel Tired After Eating & What To Do About It
HomeHome > Blog > Why You Feel Tired After Eating & What To Do About It

Why You Feel Tired After Eating & What To Do About It

May 31, 2023

If you find yourself feeling groggy after chowing down on a big meal, you’re not alone. In fact, there are plenty of factors that can contribute to post-meal fatigue and it’s a common issue that many experience.

Keep reading for more on why you might feel tired after eating, plus some expert-recommended tips to bump up energy levels.

Postprandial somnolence (aka feeling tired after eating) can have a few different causes, according to Jessica Cording, MS, RD, CDN, INHC, a registered dietitian and author of The Little Book of Game Changers.

She explains that the composition and size of your meals might play a role by altering blood sugar levels and certain chemicals in the brain, such as serotonin, which regulates sleep. Other factors might also have an impact, including how much sleep and physical activity you’re getting each day.

While it’s pretty normal to feel a little tired after eating from time to time, it’s probably a good idea to check in with a doctor if you’re feeling drained on a daily basis. Functional medicine consultant and weight management expert Emily Doctor, DNP, FNP-BC points out that fatigue can be a sign of many other serious health issues, including autoimmune conditions, thyroid problems, iron deficiency, anxiety, depression, and sleep disorders.

Doctor also explains that a condition called reactive hypoglycemia could also cause low blood sugar levels1 2-5 hours after eating, resulting in fatigue, sweating, and shakiness.

“As always, make sure to advocate for yourself if you feel like you might have any of these medical conditions,” says Doctor. A healthcare professional can rule out any underlying conditions and may even suggest other steps you can take to boost your energy levels.

There are several factors that could cause you to feel tired after eating. Below, we take a deep dive into a few things that might make post-meal fatigue even worse.

Loading up on foods high in tryptophan (a type of amino acid) can cause a dip in energy levels after you eat. Cording explains that tryptophan is used to produce serotonin, “which may play a role in that sleepy, full, blissed-out feeling you get right after some meals.”

If you’ve ever experienced a full-on food coma after Thanksgiving dinner, the tryptophan found in turkey might be to blame. Other common sources include chicken, fish, milk, eggs, seeds, and soybeans.

“Feeling sleepy after a meal can be a sign of excessive daytime sleepiness,” explains Nishi Bhopal, MD, an integrative psychiatrist and sleep doctor. According to Bhopal, this can often occur due to sleep deprivation. She explains that it might also be a result of disruptions in your sleep cycle due to insomnia or other sleep disorders.

According to Cording, filling up on carbs can lead to an afternoon slump, which is why you might feel tired after eating sugar or sweets.

“When someone eats a very high-carb meal that doesn’t have much protein, fat, or fiber to buffer the breakdown of those carbs, they may get a short-lived energy spike as their blood sugar surges2,” says Cording. “But then they experience fatigue related to the blood sugar crash that follows.”

In some cases, feeling sleepy after a meal could be a sign that you’re not getting enough physical activity in your routine, according to Bhopal. In fact, physical inactivity is a common cause of fatigue3. Research shows that a sedentary lifestyle can have a huge impact on health and may impair metabolism4, slow circulation, and decrease insulin sensitivity, all of which can contribute to low energy levels.

If you find that you’re frequently feeling tired after every meal, it might be time to try lightening things up. “Your body has to work pretty hard to digest a large meal and absorb those nutrients, which also leads to a rise in blood sugar,” says Cording.

This can then cause blood sugar to plummet, zapping your energy levels in the process. Plus, some research suggests that eating heavy, high-fat meals might also play a role by altering levels of certain hormones involved in fatigue5, including interleukin-1.

Several strategies can help fend off post-meal fatigue. Here are a few expert-recommended tips to stop feeling tired after you eat.

“Make sure your meals and snacks provide a balance of protein, healthy fat, and carbohydrate, with adequate fiber,” says Cording. Not only can this help promote a sustained rise in blood sugar levels6, but it can also supply the important nutrients you need to stay energized after you eat.

Ensuring that you’re getting enough sleep each night is crucial for keeping energy levels up after meals. Most adults should aim for at least 7 hours of sleep each night7. If you’re having trouble getting enough shut-eye, try setting a consistent sleep schedule, removing electronic devices from the bedroom, and avoiding large meals, caffeine, or alcohol before bed.

Cording recommends having several small meals spaced throughout the day rather than a massive meal in a single sitting. Research suggests that this could support better blood sugar control8, keeping energy levels steady during the day. Sticking to a consistent eating schedule is also crucial. In fact, one study found that skipping breakfast could drive up blood sugar levels9 after lunch and negatively impact the body’s insulin response.

If you’re often experiencing an energy crash after you eat, Cording notes that keeping a log of what you’re eating might be beneficial. She explains that it can help you pinpoint the specific foods or eating patterns that affect your energy levels the most, making it easier to determine what changes you should make to your diet or lifestyle.

Incorporating more physical activity into your daily routine can bump up energy levels and fight fatigue. Not only can exercise enhance sleep quality10, but it can also help optimize the health of the mitochondria11, which are responsible for generating energy for the cells throughout your body.

Aim for at least 150 minutes of moderate-intensity exercise weekly12, which can be divided up into smaller chunks throughout the week to make it more manageable.

If you feel a food coma coming on, here are a few easy ways to crank up energy levels fast.

Consider squeezing in some movement after your meal, even if it’s just for a few minutes. “This helps balance your blood sugar and if you manage to get outside, the light exposure can also give you an extra energy boost,” says Cording.

For best results, try taking a walk right after you’re done eating. A recent study found that walking immediately after a meal led to greater improvements in blood sugar control13 compared to exercising before eating or after a longer interval.

Some people find that drinking a glass of water after a meal can provide a quick zip of energy. Not only can water support healthy digestion, but it can also prevent dehydration, which can worsen feelings of tiredness.

Even if taking a walk isn’t always doable, getting some sunlight after you eat can help. Some studies have found that exposure to light after meals might fend off fatigue and increase alertness. In fact, researchers concluded that bright light exposure after lunch reduced post-meal sleepiness14 and offered a similar set of benefits as taking a short nap.

According to Cording, foods that spike blood sugar levels can be common culprits of post-meal fatigue. As a general rule of thumb, she recommends cutting back on refined carbs, ultra-processed foods, and added sugar, all of which can drive up blood sugar. “Some people may also find it helpful to limit high-fat foods to smaller portions,” adds Cording.

Foods high in tryptophan—including meat, eggs, dairy products, seeds, peanuts, and soybeans—can also contribute to feelings of fatigue.

However, there’s no need to cut these nutrient-dense foods out of your diet altogether. Instead, try moderating your portion sizes and enjoying alongside an assortment of other healthy foods instead.

If you find that you’re constantly feeling tired after eating lunch or dinner, sticking to high-fiber, minimally processed foods is your best bet. Some examples of ingredients to stock up on include:

Enjoying a variety of nutritious meals as part of a well-rounded diet can help provide you with plenty of energy to power through your day. Here are a few healthy meal ideas to help get you going:

Many factors can contribute to feeling tired after you eat, including eating high-carb or heavy meals or consuming foods high in tryptophan, such as animal products. Other factors can also play a role, including a sedentary lifestyle and not getting enough sleep.

Sticking to a consistent eating schedule, enjoying a balanced diet, and staying active are a few simple ways to boost energy levels after eating. You can also try taking a walk after meals, going outside, or drinking some water for a quick burst of energy.

Fatigue after eating can be a symptom of diabetes. However, if you feel tired after eating, it doesn’t necessarily mean that you have diabetes, as many other factors can also contribute. Consider consulting with a doctor to rule out diabetes or other health conditions.

Although feeling tired after eating isn’t always a cause for concern, it’s definitely worth looking into if it’s a routine occurrence. For managing occasional fatigue, consider limiting foods high in refined carbs and sugar, and trying out some of the tips listed above to increase energy levels after you eat.

Rachael Ajmera, MS, RD is a registered dietitian and writer based in San Francisco. She holds a master's degree in Clinical Nutrition from New York University and an undergraduate degree in Dietetics.

Rachael works as a freelance writer and editor for several health and wellness publications. She is passionate about sharing evidence-based information on nutrition and health and breaking down complex topics into content that is engaging and easy to understand.

When she's not writing, Rachael enjoys experimenting with new recipes in the kitchen, reading, gardening, and spending time with her husband and dogs.