Fuel Up with Carbs--Carbs, and a Touch of Protein

Carbohydrate is getting a bum rap. Years of research have shown that eating about 65% of your diet as carbohydrate and 15 to 20% each of protein and fat is best for endurance performance as well as overall health, yet popular authors (like Barry Sears in his book Enter the Zone) now advocate high protein and fat diets—30% protein and fat.

Medical research shows that carbohydrate is the body’s gas. It’s converted in your body to glycogen, the fuel that allows you to train and play hard. Without glycogen in your muscles, it doesn’t matter. You won’t win that race, or walk that walk, or, as it turns out, even think that thought. Yes, carbs are actually also brain food.

Your body attempts to keep glucose levels constant because it’s the fuel your brain uses. If glucose levels are low, your body protects the brain by manufacturing it from whatever’s available—and in the absence of glucose it will cannibalize protein from your muscles. You’ll feel lousy—lethargic, slow—and your sweat will smell like ammonia from the byproducts of breaking down your own muscle tissue for energy.

Okay, so now you know—carbohydrate is the best fuel for endurance activity. But what’s little understood is the matter of timing. You need carbs before, during and after exercise. Here’s why:

• Before Exercise. A male needs 80 to 100 grams of carbohydrate within one hour of a workout, a woman about 60 grams. A PowerBar contains about 45 grams of carbohydrate and a banana packs about 30. So a good pre-ride snack for a male cyclist would be a PowerBar, a banana and a handful of raisins. Sound like a lot of food? Although it’s no problem for non-jarring activities like cycling, swimming or walking, runners typically have to experiment to see if they can run with a partially-full stomach. But training yourself to fuel up before a workout pays big dividends—the ability to train longer and harder or to be more comfortable at a slower pace.
• During Exercise. The rule is simple—every 15 minutes, drink four to six ounces of a sports drink containing about 6% carbohydrate (check the label for the percentage in the sports drink you like). That guarantees a steady flow of carbs to supplement the pre-workout meal. If you’re going to be working out for more than 60 minutes, it’s a good idea to eat half an energy bar every 30 minutes, too. During a three-hour bike ride, for instance, what you eat in the first hour turns into fuel for the last 60 minutes. Once you get behind, you’ll never catch up.
• After Exercise. Now it’s time to re-fuel for tomorrow’s workout. But don’t wait. Research shows that during the first 15 minutes after a workout your muscles are most receptive to storing glycogen from the carbohydrate that you eat. So don’t hit the shower, hit the fridge instead and consume another 80 to 100 grams of carbohydrate. Also include some protein—the proper ratio is one part protein to four parts carbohydrate. Studies show that including a moderate amount of protein helps rebuild glycogen stores faster. A sample post-workout meal that covers all the bases: cereal and a banana with skim milk.