Protein, fat, and carb can all be used for energy, but what is used depends on type and duration of exercise. Carb (sugar) is easy energy, so we use sugar from blood/muscles/liver first. Most of us hope (and probably assume) that we burn fat; but, depending on the workout, we may not burn as much as we want.
It takes time to turn fat into energy; so, quick, high-intensity, short exercises (sprints, weight lifting, plyometrics/jumping) burn mostly sugar, since it’s available immediately. Moderate intensity workouts with short bouts of intense activity and rest (competitive swimming, basketball, football, soccer) also use mostly sugar.
As intensity decreases and time spent increases, the body burns more fat. Jogging, hiking, dancing, cycling, and recreational swimming use 50% sugar and 50% fat; and, lower intensity workouts (walking) use mostly fat. But, sugar helps turn fat into energy; so, no matter what, we need sugar for exercise. Fatigue during a workout tells us that there isn’t enough sugar to keep the muscles pumping.
Sugar stores should be full before exercising to prevent burnout. There is no increased carb recommendation when exercising for a healthy lifestyle, though. 50-65% of total Calories from carbs is plenty. Avoid high sugar food/drink immediately before exercising, because activity speeds up digestion and cause tummy trouble during your workout!
We don’t need sports drinks or gels for activity lasting less than 60 minutes, but once you exceed an hour, 30 g of carbohydrates is recommended for every 30 mins of activity. 12 oz of Gatorade has 21 g of carbohydrate.
After exercise, we need to replace sugar stores as soon as possible (within 2 hours after exercise). High glycemic foods (white bread, corn flakes, sugary drinks, pretzels, saltines, melon, pineapple) are best because they absorb faster.
Along with carbs, we need protein to repair muscle breakdown. The recovery process adds muscle mass, and without enough protein, our muscles get tired and can actually weaken! Daily protein recommendations, though, are not increased. 20-35% of total Calories from protein is enough. After exercise it is recommended to consume 20-25 g of protein within 2 hours.
So, how do we refuel? Research shows that 2 cups of chocolate milk has the protein and carbohydrate content recommended after exercise. Follow this up with a full meal within 2 hours to ensure complete replacement of energy stores. Don’t like chocolate milk? (who are you?!?!?) But really, if you don’t like chocolate milk, we just want protein and carb: where you get these is up to you. Contact me for other refueling ideas!