Skip the energy bar and fuel up with a small box of raisins instead. They’re just as portable as an energy bar, yet deliver so much more, like energy-boosting carbs and potassium, one of the most underrated sports nutrients around. Potassium naturally maintains fluid balance, helping to prevent dehydration as well as muscle cramps. But when you work up a sweat, you loose it. Conveniently, a small box of raisins provides more than 300 milligrams of this mighty mineral, nearly as much as you’d get from a small banana.