Training on an empty stomach? Your "motor" is guaranteed to run out of gas in the middle of a tough workout, because you haven't "fueled up" enough. A small pre-exercise meal is mandatory to provide energy for intense physical activity, whether it's weight training before school, practice in the afternoon, or a game in the evening. However, before starting your "engine," review these "road signs" to safely guide yourself through a successful workout:

• Before exercising, allow at least 30 to 45 minutes for digestion after consuming your pre-workout snack.
• Have water with the snack to efficiently transport nutrients to your muscles and for adequate hydration before exercise. Hydration is as important as the pre-workout snack for effective training. (See How to Beat the Number One Nutrition-Related Cause of Poor Performance.)

The following sample snacks contain energy-boosting carbohydrates, beneficial fat and muscle-building protein to help you prepare your engine for complete workouts. They take only minutes to prepare and are convenient and portable, easily stored in plastic sandwich bags. Blend 1/3 cup of each food listed in the combinations below. Total calories are in parentheses.

Double-Combo Pre-Workout Snacks

Fresh or dried fruits are excellent energy-boosters—they are sources of complex carbohydrates—and nuts have protein and heart-healthy fats. Fruit and nuts are also rich in vitamins, minerals, antioxidants and anti-inflammatory compounds, which not only enhance your immune system, but also boost recovery between workouts, practices and games.

• Apple and Almonds (345 calories)
• Banana and Brazil Nuts (435 calories)
• Cherries (fresh or dried) and Cashews (295 calories) Cherries are among the top fruits with natural anti-inflammatory substances—great for sore muscles after exercise and sports!

Triple-Combo Pre-Workout Snacks

For athletes seeking to gain weight for their sport, who therefore require more time for digestion before exercising, these triple combo snacks have more calories. Carbohydrate-rich dried fruit, popcorn and dark chocolate are heart-healthy foods (athletes need healthy hearts for endurance). Seeds and nuts have protein; and the nuts, seeds and dark chocolate also have healthy fats.