For seasoned runners, having caffeine before running has been shown to make workouts seem easier—and help the body burn calories more efficiently. Aim for about 3 milligrams of caffeine per kilogram of body weight: For a 150-pound woman, that’s about the amount in a 16-ounce coffee.
—Marni Sumbal, RD, a certified triathlon coach and sports nutritionist in Greenville, S.C.
