BEFORE For endurance, it's best to eat carbs two or three hours before exercise; for strength training, you'll need a mix of protein and carbs 30 minutes to an hour beforehand. Muscles need amino acids and glycogen for energy and to limit the damage you're doing under load. "Strength training in a fasted state will have a negative effect on muscle regeneration," says Meyer. "Six grams of proteinone egg, a glass of milk, or a cup of yogurtis probably enough, but 10 to 15 grams is ideal. More protein than that would slow down the digestive process." As for carbs, 30 grams will do. That's what's in most exercise bars or a small bowl of cereal.
DURING Water is fine unless you foolishly skipped that pre-workout meal, in which case a sports drink with a mix of carbs and protein should get you through.
AFTER As with endurance recovery, the first 30 minutes after strength training are crucial, but don't go overboard with heavy shakes loaded with 50 grams of protein. "More is not better with protein," says Meyer. "It seems that repeated, smaller amounts is more effective. This lets the muscle pick up the amino acids it needs without getting overloaded trying to clear out the extra." What you ate before your workout (yogurt, chocolate milk, cereal) works here, too, but be sure to revert to your normal diet of lean proteins, veggies, and whole-grain carbs later.