"If we're already sleep deprived, we're probably going to feel a little bit more of that crash in the afternoon more than regularly," the Cleveland Clinic's Dr. Tina Waters said. "It doesn't necessarily have to do a lot with what we're eating."
But doctors also say if your lunch is high in fat and carbs, the urge to sleep can be compounded. A 20-minute power nap is ideal, but for most workers sleeping on the job is not an option.
So what can you do to stay awake?
"Getting some physical activity, stretching your legs, moving around a little bit, get your heart rate going again, just to increase the blood flow to everything in the body," Dr. Waters said.