Lydia Kang is an internal medicine physician at Nebraska Medicine in Omaha and the co-author of “Quackery: A Brief History of the Worst Ways to Cure Everything.”
Q: I always feel sleepy in the afternoon after I eat my lunch. Why does this keep happening, and is there anything I can do to prevent it?
A: Feeling sluggish after lunch is very common. The “afternoon dip,” as it’s sometimes called, refers to those groggy hours between 2 and 5 p.m., when your eyelids droop and your concentration becomes as sharp as vanilla pudding.
There can be myriad reasons this happens, including too little sleep at night or medical conditions such as obstructive sleep apnea, anemia and thyroid disorders. If you feel exhausted, check with your health-care provider to make sure all is well.
But if you’re just feeling a dip in energy, the most likely culprit is your circadian rhythm. Our biological clock is more pervasive than you might think: Though people often only associate it with sleep and wake cycles, it’s also linked to our routines for meals and activity. Research in fruit flies, mice and humans has shown genes control clocks in the cells of our tissues — including the skin, the liver and the brain — that work on an oscillating cycle affected by light exposure.
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Studies have also shown that our alertness tends to be lowest at two points in the day: in the morning from around 2 to 7 a.m. and in the afternoon from 2 to 5 p.m. Most of us are asleep during the first dip, but that slump is highly relevant to shift workers. For people who work during the day, the second slump comes right in the middle of that boring meeting or when you might be driving home. (In fact, you’re far more likely to have a car accident after lunch than after breakfast.)
Research on other causes for the afternoon dip have been limited in scope but can give us further clues as to why it happens. After lunch, your circulation shifts to accommodate more blood flow to the digestive system, meaning less blood goes to your brain, which could trigger some tiredness. A tangled web of hormones, molecules and neurotransmitters is also at work.
One of them, orexin, is a neuropeptide in the brain that affects hunger and helps keep us awake. After a meal, when your glucose levels rise, this may inhibit orexin.
A similar phenomenon occurs with tryptophan, an amino acid that can turn into melatonin, a hormone associated with sleep. We’ve all heard those tales about turkey and tryptophan. It turns out the likely issue isn’t all about the turkey; it may also be the carbs.
Research has found that eating a protein-rich meal is not associated with a higher ratio of tryptophan in our blood. But the insulin rise caused by pairing tryptophan with high-glycemic index foods, such as potatoes, white bread and white rice, can lead to a relative influx of it into the brain and make you feel a bit sleepy.
Why? Insulin tells your body to store amino acids — the building blocks of proteins — in your cells. But it doesn’t do the same thing for tryptophan, giving it easier access to your brain.
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Based on what we know, it’s a good idea at lunch to load up on veggies, which are rich in fiber and can help regulate your blood sugar. Avoid consuming a large portion of animal protein and fat. Try eating complex carbohydrates such as whole grains and legumes, and veer away from simple carbs, including sugary drinks and white pasta.
Shaving off even small amounts of sleep for just a few days can worsen afternoon grogginess, so it’s important to get a restorative night of rest on a regular basis. A dose of a caffeinated drink early in the afternoon can help but remember that too much can disrupt your sleep and perpetuate the tiredness cycle.
A brisk walk, ideally outside, can give you a boost, as can bright natural or artificial light: One small study found that bright light exposure reduced fatigue after lunch — perhaps the only time a physician will recommend screen time.
If all else fails, a nap can help improve cognitive performance. Just keep it under 30 minutes and early in the afternoon, so it doesn’t mess with your nighttime sleep schedule.
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FAQs
Circadian rhythms: Circadian rhythms are natural fluctuations in body temperature, hormones, metabolism, and other physiological processes that operate according to a 24-hour clock. The circadian signals that promote wakefulness tend to decrease in the early afternoon, which can lead to sleepiness following lunch.
What is sleepy after eating a symptom of? ›
Feeling sleepy after eating can be a sign of diabetes, but many people who don't have diabetes also experience a slump in their energy levels following meals. This usually has to do with your blood sugar responses to what you eat.
How to stop feeling sleepy after lunch? ›
For example, taking a short walk after eating a large meal can help you stabilize your blood sugar levels, improve your energy, and avoid drowsiness. Research also shows that regular exercise can help improve your overall sleep quality. This will prevent daytime fatigue and generally make you feel more energetic.
What causes extreme afternoon fatigue? ›
In part, it is physiological: Our normal circadian cycle dictates a period of sleepiness or decreased alertness in the afternoon. However, sleep disorders, medical disorders, stress, insufficient sleep or poor eating habits can also cause excessive sleepiness at this time.
How to stop feeling tired in the afternoon? ›
13 Ways to Beat the Afternoon Slump
- Take a Walk. 1/13. Your body isn't built to be alert and productive 8 hours straight. ...
- Eat a Good Breakfast. 2/13. ...
- Do Energizing Yoga Stretches. 3/13. ...
- Drink Water. 4/13. ...
- Sip Green Tea. 5/13. ...
- Take a Break From Work. 6/13. ...
- Open the Blinds. 7/13. ...
- Try a Standing Desk. 8/13.
Is This Feeling Normal? The tendency to feel sleepy after a meal, especially after lunch, is very common—though some people experience it more strongly than others and some people don't experience it at all.
What is it called when you get sleepy after eating? ›
Scientifically deemed “postprandial somnolence,” and colloquially known as a “food coma,” feeling sleepy after eating is something most humans have experienced. However, that doesn't mean we enjoy grinding through those next couple of yawn-filled hours. Luckily, you can combat that food coma before it happens.
What is after lunch tiredness called? ›
Postprandial somnolence, which many describe colloquially as a food coma, refers to the sense of fatigue, sleepiness, or decreased energy levels that can occur shortly after eating a meal.
Does diabetes cause uncontrollable sleepiness after eating? ›
Could I have diabetes?” Yes, fatigue after eating is a possible symptom of diabetes. But it's also a sign of a poor diet in general. Whether you have diabetes or not, high blood sugar can make you sleepy, because when your blood sugar crashes, you end up feeling fatigued and sluggish.
What foods should you avoid that make you sleepy? ›
Avoiding caffeine, alcohol, spicy, high-fat, and heavy meals, as well as sugary snacks, citrus fruits, tomatoes, high-protein foods, and carbonated drinks can go a long way in promoting better sleep.
Vitamin and mineral deficiencies, including B2, B3, B5, B6, B9, B12, C, D, iron, and magnesium, are among the most common causes of unexplained fatigue. Vitamin D deficiencies affect over 50% of the global population, and approximately 12.5% have iron deficiency anemia.
Why do I get sleepy in the afternoon after lunch? ›
An amino acid called tryptophan, which occurs in many protein-rich foods, helps the body produce serotonin. Carbohydrates help the body absorb tryptophan. For these reasons, eating a meal rich in both protein and carbohydrates may make a person feel sleepy.
What is it called when you get tired in the afternoon? ›
If you feel tired in the afternoon, you're probably experiencing an afternoon slump, which is a normal part of your circadian rhythm. If you're tired all the time, it could mean that you're not getting enough sleep at night, which is a common problem.
How to beat post lunch tiredness? ›
While you may not be able to avoid it entirely, there are some things you can try to counteract the sleepiness that occurs after meals:
- Eat well-balanced meals. ...
- Get more nighttime sleep. ...
- Expose yourself to enough daylight. ...
- Get regular exercise. ...
- Nap for 10 to 20 minutes.
The afternoon energy crash is typically a result of natural physical processes—like the circadian rhythm—and lifestyle factors. Your circadian rhythm creates a natural dip in energy during the early to mid-afternoon. On top of that, the type of food you eat during the day can affect your energy.
At what age do you start feeling tired and old? ›
Well, this depends on a person's age, health, fitness level and lifestyle. Generally, the more years that pass, the more you'll value your beauty sleep, and its true senior fatigue is a real thing. However, most people start experiencing a decline in their energy levels by the time they reach their mid-thirties.
Do diabetics feel sleepy after eating? ›
Insulin sensitivity is a big reason that people with diabetes may fall asleep after eating. People with diabetes may not produce enough insulin or are unable to use it correctly. The lack of energy that occurs when insulin doesn't work correctly can cause people to experience drowsiness.
What does diabetes fatigue feel like? ›
Many people with diabetes will describe themselves as feeling tired, lethargic or fatigued at times. It could be a result of stress, hard work or a lack of a decent night's sleep but it could also be related to having too high or too low blood glucose levels.
What is the sleepy hormone after eating? ›
After a meal, when your glucose levels rise, this may inhibit orexin. A similar phenomenon occurs with tryptophan, an amino acid that can turn into melatonin, a hormone associated with sleep.
What food makes you sleepy? ›
Melatonin (found in dairy and cherries) makes you sleepy, potassium (found in bananas) and magnesium (also found in bananas and almonds) help promote muscle relaxation. Furthermore, many herbs, often found in teas like chamomile and mint are considered sleep inducing, while the dairy in warm milk is effective as well.
