The surprising reasons why you feel tired after a meal

You're grumpy because all you want is a breakfast burrito before you go out and conquer your day. Once you're full, you may not be as hungry, but you'll be more tired than if your alarm clock woke you up. Figuring out why you feel tired after eating might be the secret weapon you need to make those post-brunch weekend errands truly unstoppable.

"Feeling a little tired after a big meal is usually normal and nothing to worry about," says Alyssa Pike, registered dietitian and nutrition communications manager at IFIC. But if the food gives you energy , why does eating make you feel tired?

Why do I feel tired after eating?

Especially if you go from super hungry to full in a short amount of time, it could be your lizard brain that's making you sleepy. "From an evolutionary perspective, food wasn't always readily available," Pike tells Bustle. In this case, "it might make sense that we would feel relaxed after a full meal. The hypervigilance associated with hunger has subsided and we are free to rest."

On the other hand, your need to nap after a meal may mean you're still hungry. "If we still feel tired after eating, it's probably because we're not eating enough—that is, providing our bodies with enough energy—to sustain us throughout the day," Pike says. If you're exhausted after refueling, you may want to pack some extra snacks.

You may also have hidden food intolerances that cause you to be drowsy after meals, for example, when you drink milk and you are lactose intolerant, your digestive system needs to go into overdrive and all the extra work can Makes you tired. Pike also notes that conditions like chronic fatigue or anemia can make you feel exhausted after meals, so if food consistently drains you instead of energizing you, you may want to talk to your doctor.

Do certain foods make you more tired?

"Researchers don't entirely know why we feel tired after eating, but one hypothesis is that certain foods may influence this sleepiness," Pike explains. Giving yourself sugar or caffeine may cause a crash after a burst of energy, while certain foods may make you feel tired from jumping.

Tryptophan is an amino acid found in high-protein foods—think turkey—that is, the oft- cited culprit behind post-holiday naps. Peck told Buster that tryptophan helps the body produce the neurotransmitter serotonin, which helps regulate sleep. "Increased serotonin production may be responsible for post-meal sleepiness," she says.

Foods high in protein and salt (marinated tofu sandwiches, anyone?) make fruit flies very sleepy, according to a 2016 study published in the journal eLife . Scientists think this effect could apply to humans, which might explain why you take a nap after a meal.

How can I not feel so tired after eating?

Sometimes a brunch host's goal is to provide everyone with a food coma. However, if you have to cross eight million things off your to-do list that afternoon, there's no universal formula for what you should eat to keep yourself awake, Peck says.

"When it comes to nutrition, trial and error is often your best chance of figuring out what works best for you," she explains. "See if you notice a difference after eating different portion sizes. See if eating more frequently and/or mixing in macronutrients (aka carbs, protein, and fat) can help you feel more energetic."

Not sure where to start with a food somnolence test? "In general, it's helpful to have a variety of foods at each meal because each macronutrient provides our bodies with essential energy and nutrients," Pike tells Bustle. "The combination of all these nutrients can help us feel more energized after a meal." That's exactly what you want in the first place.

Research references:

Murphy, KR (2016) Postprandial sleep mechanisms in Drosophila. electronic life.


Alyssa Pike, R&D, Nutrition Communications Manager, International Food Information Council (IFIC)