This past weekend I attended a state-of-the-art sports nutrition conference sponsored by SCAN, the Sports and Cardiovascular Nutritionists practice group of the American Dietetic Association. I had the pleasure of listening to the top researchers offer their latest sports nutrition news. Here’s what researcher and registered dietitian Louise Burke, PhD, Director of Sports Nutrition at the Australian Institute of Sport, had to say about carbohydrates.
DAILY CARBOHYDRATE NEEDS
• Don’t try to calculate a diet according to “percentage of carbohydrates”—such as a diet with 60% of the calories from carbs (a typical recommendation for athletes). Rather, define your daily carbohydrate needs in terms of grams per pound (or kilogram) body weight. The guidelines developed by the International Olympic Committee are:
Low intensity exercise: 1.5 to 2.5 g Carb/lb (3-5 g Carb/kg)
Moderate exercise (~1 hour/day): 2.5 to 3 g Carb/lb (5-7 g Carb/kg
Endurance exercise (1-3 hours/day): 2.5 to 4.5 g Carb/lb (6-10 g Carb/kg)
Extreme exercise (>4-5 h/day): 3.5 to 5.5 g Carb/lb (8-12 g Carb/kg)
Hence, if you are a serious athlete who weighs 150 pounds and trains for 2 hours a day, you’d need about 375 to 675 g carbohydrate per day. One grams of carbohydrate offers 4 calories, so this equates to 1,500 to 2,700 calories of carb to fully fuel (and refuel) your muscles. This is more carbohydrate than many endurance athletes tend to consume when eating on the run.
• By hitting your carbohydrate targets, you can restore depleted glycogen stores within 24 to 36 hours post exercise.
CARBS DURING EXERCISE
* If you will be exercising for less than 45 minutes, you have no need to consume carbs (such as a sports drink) during exercise. What you eat pre-exercise will carry you through the workout.
• If you will be exercising for 1 to 2.5 hours, you should target 30 to 60 grams carbohydrate per hour. Your pre-exercise snack should carry you for the first hour, and then you’ll want to target 120 to 240 calories of carbohydrate per hour thereafter. This equates to 120 to 240 calories from carbohydrate.
• If you will be exercising for more than 2.5 hours, you should target 60 to 90 grams of a variety of carbohydrate per hour (as tolerated). That’s 240 to 360 calories from sports drinks, dried pineapple, gels, gummi bears, and other carbs that taste good and settle well. Be sure to practice fueling during training, so you know what foods and fluids work well – and what ones don’t!