Why Does Lunch Make Me Sleepy?

A dietitian explains why you want to nap after lunch, and what you can eat that won’t immediately knock you out.

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For many of us, lunch is followed by a single thought: Is there a way I can take naps breaks at work? But what exactly is it about our midday meal that sends us straight to dreamland? Liz Weinandy, resident dietitian at The Ohio State University Wexner Medical Center, says it’s a combination of carbohydrate overload and our body’s natural sleep schedule.

When we eat too many carbohydrates—say, a burger with a side of fries, or a sandwich with potato chips—our blood sugar surges. Our bodies react to this surge by producing insulin, which is the hormone that regulates our blood sugar levels. “Unfortunately, this process happens rather quickly when we’ve eaten too many carbohydrates,” Weinandy explains. That means we go from having relatively high blood sugar to relatively low blood sugar—both of which are known to cause tiredness—in a fairly short period of time. In other words, we’re feeling the tiring symptoms of two bodily processes at once.

There’s also the fact that our circadian rhythmaka, the body’s internal clock—is literally programmed to make us tired right after lunchtime because our sleep schedule works in 12-hour shifts. That’s why we generally become most tired between 2:00am and 4:00am and between 1:00pm and 3:00pm—or, the middle of the night and just after lunch. These bouts of sleepiness can be lessened fairly easily, though: Just get somewhere between seven and eight hours of sleep the night before (or how ever much sleep you feel you need to not feel tired in general).

That said, the most effective way to avoid the post-lunch slump is to cut down on carbohydrates and to always eat them with some kind of protein. “Protein helps to slow down that tiring blood sugar response,” Weinandy explains, “So you can still eat that burger if you want to.” Just substitute the fries with a greens-filled side salad.

If you can’t (or won’t) ditch the side of fries, we recommend taking your post-lunch nap in a bathroom stall—it’s more comfortable than you’d think.