Why Am I Always So Tired After Lunch?
Expert Verified By: Dr. Shelby Harris 
Most of us are intimately acquainted with the afternoon slump, when we struggle with zapped energy and an almost unbearable desire to curl up for a nap. But what’s really going on? Why are we so tired after lunch? We tapped three sleep experts for a little insight, plus their tips for staying alert until it’s time for bed.
Why Do I Get So Tired After Lunch?
First things first — feeling sleepy after a meal is common, says Kelly Murray, a certified pediatric and adult sleep coach. It’s known as postprandial somnolence, and there are a few things at play, including our normal circadian rhythm (that unfortunately doesn’t care about your work schedule!), our digestive cycle, and what we choose to eat.
Natural Circadian Rhythms
According to Dr. Shelby Harris, Sleepopolis’ director of sleep health, there are natural ebbs and flows to the circadian rhythm.
“It’s actually pretty normal to have a dip in your circadian rhythm after lunchtime,” she says. “It’s not about being awake all day and then asleep at night.”
Harris suggests pushing through the afternoon sleepies by “[resting] a little bit, get some light, a little coffee earlier in the afternoon… and you should be good to go.”
The Digestive Cycle
Pair this natural ebb in the circadian rhythm with what’s going on with our digestive systems, and things become even more clear. “Digesting a big meal can require a lot of energy,” says Stephen Light, certified sleep science coach and CEO/co-owner of Nolah Technologies. That means what you eat for lunch — and how much — has a direct effect on how tired you may feel afterward.
The process of digesting food and turning it into energy triggers all sorts of mechanisms in the body. Our bodies break down the foods we eat into glucose, or fuel, which provides the calories we need to function. Throughout this process our blood sugar increases, and insulin production begins so that the circulating sugar can be efficiently moved from the blood into the cells — that’s where it’s used for energy. But all that work requires increased blood flow, which brings us to the role of the circulatory system.
Circulation Shift From Brain To Stomach
“Postprandial somnolence or sleepiness/tiredness after lunch is often associated with a shift in blood flow to the digestive system to process the food consumed, which is perfectly normal,” explains Dr. Carleara Weiss, a member of the American Academy of Sleep Medicine and sleep advisor to Pluto Pillow. That shift can make us feel drowsy, particularly in combination with everything else that’s going on.
Foods That Induce Sleepiness
What we eat can also alter our hormonal balance, says Light. “For example, some foods contain melatonin or tryptophan,” both of which can make you feel tired. “Large meals and foods high in protein, refined carbohydrates, and fat are more likely to make you feel tired,” he says.
Tryptophan is common in high-protein foods, including:
- Poultry
- Salmon
- Eggs
- Soy products
- Cheese
- Seeds
- Spinach
High-carbohydrate foods include:
- Pasta
- Rice
- Milk
- Baked goods, like bread, crackers, muffins, cookies, cakes
- Candy
Foods That Help Avoid An Afternoon Crash
Just as there are foods that can contribute to that afternoon energy nosedive, there are choices that can help keep you energized. “Healthy and light meals are good options to avoid this food coma and afternoon crash,” says Weiss. That means a balanced meal with lots of vitamins and minerals, so you’ll still be incorporating carbs, proteins, and healthy fats. But be choosy.
“Rolled oats, whole grain pastas, multi-grain bread, chickpeas, and even sweet potatoes are slow-releasing carbohydrates. They’re low on glycemic index, which helps keep our blood and energy levels as well as appetite more steady,” says Murray. Unlike high fat and processed carbohydrates that cause big spikes and drops in our blood sugar — which is reflected in our energy levels and mood — these foods help us stay steady for prolonged periods.
Tips For Staying Alert After Lunch
In addition to being mindful about what’s on the menu for lunch, there are a few other ways to hack your system and avoid that afternoon slump.
- Get outside. Sunshine and fresh air can help you feel more alert and energized. That’s because the circadian rhythm is strongly influenced by light, which is a signal to be awake.
- Get some exercise. Even a short, brisk walk increases oxygen flow in the body for a quick energy boost — research shows it’s better than a cup of coffee!
- Stay hydrated. Mild dehydration can make the body feel more tired and weak than normal, so make sure you’re sipping water all day long.
- Avoid alcohol. Alcohol is a sedative — it depresses the nervous system. That’s why daytime drinking can make you feel lethargic.
- Get better sleep the night before. “Staying alert after lunch is a consequence of a bedtime routine, a good night’s sleep, and a good wake-up routine,” says Weiss. Stick to a consistent sleep schedule, exercise regularly, and eat a healthy diet, and you might find that postprandial somnolence really isn’t much of an issue.
Health Conditions To Consider
Some health conditions, including any of the following, can make post-meal drowsiness worse.
Diabetes
Feeling tired after eating can be a symptom of diabetes. People with diabetes either don’t produce enough insulin or their bodies don’t use it effectively, which means cells have a hard time absorbing glucose from the blood. “Elevated blood sugar, also known as hyperglycemia, can cause fatigue after a meal,” says Murray. “The opposite can happen as well. If someone has low blood sugar, postprandial hypoglycemia can cause weakness.”
Anemia
People with anemia, a condition in which red blood cells aren’t carrying adequate amounts of oxygen throughout the body, often experience fatigue and weakness, including after eating. If you think you have anemia, it’s worth talking with your doctor about testing and treatment, which may include adding iron or B-12 supplements to your diet.
Sleep Apnea
According to the Food & Drug Administration, an apnea is a pause in breathing for at least ten seconds. Untreated sleep apnea is highly disruptive to sleep, making you feel really tired in the morning. This kind of sleep deprivation can make that afternoon slump much more pronounced, since you’re already exhausted.
Food Intolerance Or Allergy
Fatigue can be a response to food sensitivities, intolerances, or allergies. The body allocates energy to manage the effects of the sensitivity, leaving you feeling drained and ready for a nap. Some of the symptoms of food allergies or intolerances, such as migraines or crampings, can trigger a stress response, which can also trigger fatigue.
Celiac Disease
Celiac disease is an inflammatory disorder triggered by gluten, and overwhelming fatigue is a common symptom. It’s worth speaking to a doctor if you’re experiencing this level of exhaustion, particularly if it’s paired with intestinal distress and general abdominal problems after eating gluten in wheat, rye, or barley.
Thyroid Issues
“If an individual has an underactive thyroid, it can cause low points of fatigue throughout the day, which can be linked to mealtime,” says Murray.
When To Consult A Doctor
Feeling sleepy after lunch isn’t uncommon, but if you have any concerns that what you’re experiencing is more serious than a food coma or afternoon slump, see your doctor. “People should also consult their healthcare provider if they experience extreme and recurrent fatigue and sleepiness during the day, with a high risk of falling asleep while talking, working, sitting in a car, or driving,” says Weiss.
The Last Word From Sleepopolis
If you’re desperate for a nap not long after lunch, you’re certainly not alone. There’s a natural dip in our sleep/wake cycle in the afternoon, but being mindful of what you’re eating can help you stay alert. A little exercise, good hydration, and prioritizing consistent bedtimes and wake-up times are other ways to avoid that dreaded afternoon food coma.
Keep in mind that feeling excessively tired after eating can be a sign of certain health conditions. If you have any concerns, or you’re experiencing after-meal exhaustion in addition to other symptoms, make sure to bring it up with your doctor.
