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The answer: What to eat before you exercise depends on the type of workout you will be doing. If you're doing a strength workout (e.g. weights, circuit training, boot camp) your snack should provide carbohydrate to fuel your muscles during exercise and protein to help your muscle tissue recover after exercise.

Snack options to eat 45 to 60 minutes before a strength workout include an energy bar (look for 20 to 25 grams of carbohydrate and 10 to 18 grams of protein), a smoothie made with fruit and milk or soy milk, yogurt and berries, a hard-boiled egg and an apple, or half a turkey sandwich.

If your cardio workout (e.g. power walk, run, elliptical trainer) is less than an hour, you don't necessarily have to eat a pre-workout snack. Providing your meals include carbohydrate-rich foods such as whole grains, legumes and fruit, you can rely on your muscle glycogen (energy) stores to get you through. If you exercise in the morning and you're trying to lose weight, research suggests eating breakfast after – rather than before – a cardio workout allows you to burn more fat.

If your cardio workout is an hour or longer, eat a carbohydrate-rich snack at least 45 minutes before to supply glucose to your bloodstream. Your snack should be 100 to 200 calories; larger snacks take longer to digest. Easily digested snacks include a smoothie, a banana, three-quarters of a cup of yogurt, an energy bar, a whole grain cereal bar and a small serving of oatmeal. Foods high in protein, fat or fibre take longer to empty from your stomach and are likely to cause digestive upset while you are working out.

Post-workout snacks are important, too. After a cardio workout, eat a carbohydrate-rich snack if your next meal will be more than an hour away. Carbohydrates replenish the glycogen your muscles burned during exercise.

After a strength workout, you need carbs as well as 10 to 20 grams of protein to help repair and rebuild muscles tissue. Protein shakes (made with milk and/or fruit), energy bars, three-quarters of a cup of Greek yogurt and fruit, even a sandwich with lean protein all work well.

And of course, be sure to drink water before, during and after exercise to help stay hydrated. Water is fine for workouts less than an hour. But if you're exercising longer, hydrate with a sports drink, which replenishes water and electrolytes (sodium, potassium, chloride) lost through sweat. Aim to drink five to 12 ounces of fluid every 15 to 20 minutes.

Leslie Beck, a registered dietitian, is the national director of nutrition at BodyScience Medical. She can be seen every Thursday at noon on CTV News Channel's Direct ( ).

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