The workout: Boot camp or a weight session with your trainer.
Pre-workout carbs give you energy, so have your 30 grams if you're really hungry. However, it's what you eat after the strength-training session that really matters—even more than after cardio workouts. Protein helps repair muscles and provides raw material for building new ones, says Rosenbloom. Aim for 10 to 20 grams of high-quality protein (not the fried chicken nuggets she's seen some college athletes sneak into the locker room).