Tired After Eating? 5 Potential Causes & Ways To Prevent It, From Nutrition Experts

If a good meal leaves you ready for a nap, you're not alone. Fatigue after a meal is a surprisingly common phenomenon—and we're not just talking about how you feel after Thanksgiving dinner. From hormones to food sensitivities, there are a number of potential culprits for that afternoon slump. Luckily, there are also a few workarounds.

A high-carb meal, in particular, can trigger a rise in insulin. "When these insulin levels peak after eating, this can lead to a crash in our blood sugars—leading, understandably, to that all-too-familiar post-lunch slump—a foggy brain and tired body," says Uma Naidoo, M.D., nutritional psychiatrist, professional chef, nutrition specialist, and author.

There is evidence linking random mealtimes with increased fatigue2, and one study found that eating a large lunch after skipping breakfast actually contributes to less blood flow in the brain. Not only does that make it harder to focus, but it can also lead to fatigue. "Without the ample flow of blood, the brain conserves its essential functions, and we may become more drowsy," says Naidoo. So if you omit breakfast as part of intermittent fasting, for example, consider slowly transitioning back into eating with a mini-meal (you can learn all about that technique here).

Telltale fatigue is even more noticeable if you're drinking alcohol with your meal. "While a glass of fine wine may complement your meal, alcohol functions as a central nervous system depressant," says Naidoo. "As such, having a bit too much to drink may contribute to feeling fatigued after a meal."

If you're already dragging, a meal has the potential to make you feel even more exhausted. Naidoo explains that it's because both your ability to metabolize sugars and even your appetite3 could be impaired.

Identifying what may be causing you to crash and burn after a meal is one thing, but avoiding it is another. Fortunately, there are simple steps you can take to help keep your energy levels high and minimize those sleepy feelings after you eat:

Naidoo advises adjusting your meal composition—specifically, decreasing carbs and including more protein- and fiber-rich foods. "In doing so, we optimize nutrients that keep our blood sugar levels steady: Both protein4 and fiber5 are known to improve glycemic control. Also a fiber-rich meal means extra love for your gut, as our gut microbes thrive on fiber." There's also evidence6 that a veggie-rich diet with ample amounts of healthy fats reduces post-meal sleepiness.

And here's Naidoo's pro tip: "Research suggests that including vinegar7 in carbohydrate-rich meals may improve glycemic control and, subsequently, prevent post-meal fatigue."

Sleep deprivation wreaks havoc on the metabolism, but there is good news. "Just one night of adequate sleep can reverse the negative effects8," says Naidoo. And in a pinch, a post-lunch nap9 can work wonders. 

There's a lot of contradictory information out there when it comes to diet, but one thing is clear—eating regularly matters. "The body performs best while operating on a consistent schedule with sleep, wake, and scheduled mealtimes," says Naidoo. "This encourages balanced energy, constant blood to nourish the brain, and appropriate hunger cues—all contributing to optimal alertness and mental clarity."

In other words, maintaining regular mealtimes can help you stave off those post-meal yawns.

Regular exercise has a laundry list of benefits, and chief among them is that signature energy boost. Commit to moving your body regularly, shooting for 30 minutes every day. But keep in mind, even a post-lunch lap or two can be enough to keep your energy levels high.

Even minimal levels of dehydration can contribute to feelings of fatigue. Sipping water during the day is an easy way to stay alert, among a multitude of other benefits.

If you're regularly fighting to keep your eyes open after a meal, you aren't alone, and a little detective work can be a game-changer. Naidoo notes that one of the pillars of nutritional psychiatry is body intelligence, which simply means paying attention to your body's cues before, during, and after meals. Sounds simple, but we're likely all guilty of multitasking when we eat. Eating mindfully gives us the opportunity to really assess what's going on. What makes us feel good? What isn't serving us? What might have led to this post-meal crash, and what steps can we take to avoid that next time?

"If you're unsure where to start, focus on adding colorful, fiber-rich, and antioxidant-packed vegetables and fruits to your plate," says Naidoo. "The added nutrients fend off fatigue, and fiber nourishes the gut, which, in turn, encourages a healthy brain."