Tired After Lunch? Try This

Feeling drowsy after lunch is common, but a few simple tips can help

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At some point, everyone has felt like they could really, really use a nap after lunch. The phenomenon of the "afternoon slump," or post-lunch drowsiness, is so common that the medical community has given it an official name—postprandial somnolence.

The post-meal feeling of tiredness and lethargy can make it hard to concentrate on afternoon work and often puts a heavy damper on post-lunch productiveness.

The reasons behind the "afternoon slump" are varied, but a few easy tips can help banish this fatigue and keep energy levels stable throughout the day.

The Circadian Element

It’s normal to feel a dip in afternoon energy levels and alertness because of our bodies’ natural circadian rhythms. This internal, biological body clock helps regulate sleep-wake patterns, which involve a host of different hormones and biological processes.

Circadian rhythms are largely responsible for the experience of feeling wide awake and alert at times and drowsy at other times.

According to the Sleep Foundation, our bodies’ strongest sleep-related cues are felt shortly after midnight, and then again, to a lesser degree, in the afternoon between approximately 1 and 4 p.m. This aligns with the practice of enjoying an afternoon siesta in many countries around the world.

The Fat and Carbs Effect

There’s more to it than uncontrollable biological cues, though. What you eat for lunch can also play a significant role. An Australian study published in the October 2019 edition of the journal Nutrients found that as the amounts of dietary saturated fat and carbohydrates increased in a meal, so did the degree of daytime sleepiness. Combining large amounts of saturated fat and carbohydrates in one meal (think burger and fries) may intensify the effect.

Functional dietitian nutritionist Adair M. Anderson explains the physiological process.

“Meals high in carbohydrates (without adequate protein and fiber to slow digestion) result in blood sugar spikes, which the body fixes by releasing insulin (the key that lets blood sugar into your cells),” Anderson says. “However, sometimes (most times), the body releases too much insulin (the body really doesn't like high blood sugar), which results in a blood sugar crash. Low blood sugar is associated with fatigue.

“Meals high in saturated fat are more likely to trigger leaky gut (intestinal hyperpermeability). When the gut is leaky, things from inside the gut lumen (e.g., bacterial lipopolysaccharide and undigested food) can get into the bloodstream, usually resulting in inflammation. Inflammation is [also] associated with fatigue.”

The Portion Size Effect

It’s not just the type of food eaten, but the amount, too, which can impact how you feel an hour or so after eating. Eating large, "heavy" meals seems to result in a stronger desire for a nap shortly afterward than does eating small meals.

One study, published in the Feb. 28, 2012, edition of Physiology & Behavior, took 12 young men whose sleep had been restricted the night before and gave them either a "light" 305-calorie lunch or a "heavy" 922-calorie lunch, which contained three times the fat and twice the carbohydrates of the "light" lunch.

The men then took a leisurely two-hour, simulated "drive." Perhaps not surprisingly, for those who ate the "heavy" lunch, their driving suffered more than that of the "light" lunch eaters. The "heavy" lunch group drifted from their lanes while driving more often, and also reported feeling more tired.

Other Factors

Also, certain nutrients are actually sleep-promoting. Tryptophan, an amino acid that's often blamed for the sluggishness that many feel following their Thanksgiving meal, is certainly associated with promoting sleep. A Turkey dinner at 6 p.m. may be a better idea than having it at noon. But tryptophan isn't the only sleep-inducing food around. Foods that contain high concentrations of melatonin, such as tart cherries, mushrooms, tomatoes, and pistachios, can also help regulate your circadian rhythm and promote sleep.

Other, non-dietary factors can also influence how you feel at 2 p.m. Not getting enough sound, uninterrupted sleep at night can lead to excessive daytime sleepiness, and certain medical conditions such as diabetes, anemia, and even food intolerances can also exacerbate the problem.

Steps to Stay Awake

While the dreaded afternoon slump can have various causes, some simple steps can help stabilize energy levels in the afternoon, and all day long.

Replacing refined and simple carbohydrates, such as white bread, donuts, and sodas, with complex carbohydrates, such as whole-grain bread or brown rice, beans, and vegetables, is a major step in the right direction. Complex carbohydrates, which usually contain fiber, vitamins, minerals, and other nutrients, take longer to digest than simple carbohydrates and are less likely to cause spikes in blood sugar, which eventually "crash," leaving you tired again.

Eating a smaller portion at lunchtime, and then having an afternoon snack, instead of consuming a single, large meal, may also help ease the energy-consuming work your digestive system has to do.

Anderson points to research showing that the order in which the parts of a meal are consumed can also make a difference.

“Start with a vegetable appetizer. For example, a handful of sugar snap peas, cherry tomatoes, celery, and carrot sticks. The fiber in these low-calorie vegetables acts like a goalie net, preventing your digestive enzymes from quickly attacking (and breaking down) carbohydrates into simple sugars. The slower carbs digest, the slower they enter the bloodstream, and the more gentle the blood sugar spike (in fact, ideally it's a low, rolling hill and NOT a spike). Then, eat protein before carbohydrates (e.g., eat the chicken and broccoli first, eat the dinner roll second),” Anderson says.

Staying hydrated throughout the day can also help ward off fatigue. Water is essential for nutrients to be effectively transported to cells throughout the body, and dehydration can leave you feeling tired.

An August 2010 review titled “Water, Hydration, and Health,” published in the journal Nutrition Reviews, explains how even mild dehydration actually causes cells to shrink and can lead to cognitive declines, including short-term memory loss and reduced concentration and alertness.

Drinking plenty of liquids (ideally water) throughout the day can help both your mind and body function at their best.

Getting out for an after-lunch walk is also a great way to keep energy levels stable throughout the afternoon. Exercise boosts the delivery of nutrients and oxygen throughout the body, including the brain, and can help you stay alert. Combined with being mindful of what and how much is on your lunch plate and staying hydrated, you can stay focused and fully awake, even at 4 p.m.