The Real Reason You Feel Tired After Eating—and How to Get Your Energy Back
Have you ever eaten a hearty breakfast or healthy dinner only to feel sluggish and sleepy instead of energized? It turns out there are actually a variety of reasons you might feel tired after eating—each leading you to run into that dreaded post-lunch slump or experience early morning fatigue.
Feeling tired after eating is pretty common, and there are a slew of reasons why your food can act as the opposite of fuel. The first? Digesting a meal is a lot of work.
“If you think about it, our body is a well-oiled factory,” says Melissa Prest, D.C.N., R.D.N., C.S.R., a dietitian at the National Kidney Foundation of Illinois. “It kind of works like this: The food goes in and starts going along on a conveyor belt. Different machines are at work to break down the food, packaging it for specific purposes, and shipping it to places that help your body continue to do its work. Obviously, this takes a lot of energy, which can make someone feel tired.”
What’s more, insulin—a hormone made by your pancreas that controls your blood sugar—has a major impact on your energy levels after you eat. When you chow down, your insulin levels spike to make sure your blood sugar levels are where they should be, Prest explains. “When that job is done, insulin levels decline, which can make people feel tired. It is a normal process and sleepiness should not last that long,” she says.
To avoid that post-meal slump, Prest suggests incorporating a mix of complex carbs, healthy fats, and lean protein into every meal, and opting for foods that are lower in saturated fats, high in fiber, and minimally processed. Moving your body every day, getting at least seven hours of sleep each night, and staying hydrated will also keep you going until bedtime.
Still feeling tired after eating and wondering why? Ahead, find out why you may be ready to hit the hay after lunch.
Why do you feel tired after eating?
1. You drank alcohol with your meal
Your glass of wine could be spurring your post-meal drowsiness. Alcohol is a sedative, meaning it can leave you feeling pretty low energy, according to Harvard Health experts.
“Alcohol suppresses our central nervous system, causing us to feel sleepy,” Prest explains. “This sedative effect does not last long, but drinking alcohol close to your bedtime disrupts the sleep cycle, meaning you will not have a very restful sleep.”
So, stick to just one drink a day if you’re a woman and two max if you’re a man—or skip the booze entirely if you notice it impacting your energy levels regularly.
2. Your meal was high in fat and carbs
Comfort foods are delicious, but can often make you feel sluggish if they’re high in fat and carbs. The hormone cholecystokinin (CCK), which is released from the small intestine, is often to blame here.
“If you ate a slice of cheese pizza, which is typically a higher-fat and higher-calorie food, CCK is released and helps the body break down the protein and fat in that slice,” Prest says. “Some research has shown that there is a relationship between the increase of CCK after eating a high-fat meal and feeling sleepy a few hours later.”
When you dine on foods known to increase inflammation, like red meat or sugary sweets, your body can release cytokines (agents that help your immune cells communicate with each other), like interleukin-1 (IL-1). “Research has shown that higher levels of IL-1 after a meal is associated with post-meal sleepiness,” Prest says.
3. Certain hormones are thrown out of whack
“When tryptophan-rich foods are eaten in a large quantity at a meal, particularly with carbohydrate-rich foods, you may find that you feel tired a few hours after eating,” Prest explains. Cue your classic, post-Thanksgiving nap.
Tryptophan is often found in turkey, chicken, milk, bread, chocolate, canned tuna, cheddar cheese, peanuts, oats, and more. The essential amino acid helps your body make the relaxation-inducing hormones serotonin and melatonin, explains Prest. Because of this, it’s even been researched as a treatment for sleep disorders, such as insomnia.
4. Or you ate a pretty big lunch
Sometimes, feeling tired after you eat has more to do with how much you ate instead of what you ate. The reason is simple: “The bigger the meal, the more energy it takes for your body to break it down,” Prest says. Expending all that energy can then lead to fatigue, so try to reduce your portion sizes and reach for a high-protein snack if you get hungry in between meals.
5. A hidden food intolerance could be to blame
Food intolerances, or even full-blown food allergies, are often associated with uncomfortable GI symptoms like stomach cramping or diarrhea. But occasionally, a food intolerance you’re not aware of yet can make you feel wiped out.
For example, whether you have gluten sensitivity or celiac disease, “you may feel tired after eating foods containing gluten because it can trigger an allergic reaction,” Prest says. That can limit your body’s ability to properly fuel itself from the food you ingested, leading to tiredness.
6. Your caffeine addiction isn’t doing you any favors
Your morning cup of Joe puts some pep in your step, but not for too long. The stimulating effects of caffeine typically have a half-life (the time it takes your body to eliminate half of the caffeine) of three-to-five hours after you chug it down, which means you’ll start to feel your 8 a.m. coffee buzz drop around—you guessed it—lunchtime. So, feeling tired may be less about what you ate for lunch and more about the timing of your first cup of coffee in the morning.
7. Melatonin may be to blame
Taking a melatonin supplement can aid with insomnia and help you sleep better at night—but Prest warns that there are lots of foods high in the natural sleep aid as well, and that “eating foods high in melatonin may promote fatigue.” So if you include lots of eggs, meat, fish chicken, milk, cereals, rice, or barley in your diet, you may want to consider lowering your intake or nixing melatonin supplements.
8. You may have an underlying condition
If you’ve ruled out all the other options and you’re still constantly tired after you eat, it may be time to chat with your doctor to see if an underlying condition could be behind your symptoms.
Someone may feel tired if they have an issue that can interfere with absorbing nutrients from food, like anemia, Prest says. Additionally, hormonal imbalances, insulin sensitivity, or idiopathic postprandial syndrome (IPS) could be worth looking into, she says.
IPS is where you experience symptoms of hypoglycemia (low blood sugar levels) two-to-four hours after eating, but your actual blood sugar is in the normal range of 70 to 120 mg/dL, Prest explains. Symptoms of hypoglycemia include feeling tired, shaky, sweaty, and experiencing heart palpitations, light-headedness, or even panic attacks.
“The symptoms of IPS are like hypoglycemia, but they are usually less severe. While we do not know what causes IPS, we do know that certain things like eating foods with a high glycemic index, like sugar, drinking a large amount of alcohol, along with having a normal glucose level that drops too quickly after eating may contribute to IPS,” she says.
How to prevent feeling tired after eating
1. Balance your plate
Mindfully crafting your meals to balance protein and carbohydrates can go a long way toward turning your food into fuel. “A common method of balancing the plate is focusing on filling it mostly with non-starchy vegetables and then equal portions of a protein and starch or grain option,” Prest says.
2. Get in some post-meal movement
Take a quick, 10-minute walk after eating dinner instead of sitting down to relax and watch television, suggests Prest. A bit of light activity after a meal helps the body process and digest, leading to more energy.
3. Try bright light exposure
Prest explains that a study shows that bright light exposure can help with fatigue and contribute to better thinking after eating lunch.
4. Take a power nap
The same study mentioned above also makes a case for getting a few quick Z’s in post-lunch. In the study, those who took a power nap “had less fatigue and were better able to complete tasks,” Prest explains.
When to see your doctor
If you’ve tried the above tips for preventing sleepiness with no success and don’t identify with any of the above causes of feeling tired after eating, it’s likely time to see your doctor.
There are many other reasons you may be feeling fatigue at any point during the day, so if you find you’re always tired, schedule an appointment to ensure all your health markers are where they should be.
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