A common myth is that recovery foods consumed after a tough workout should consist solely of protein sources. This is partially true, but it's equally important to have a source of carbohydrates post-workout.
During exercise, your muscles use a combination of glucose (usable energy) and glycogen (stored energy). When these stores become depleted, your body produces the hormone cortisol, which breaks down muscle to convert protein into more glucose.
Consuming carbs post-workout not only limits cortisol production, it also allows your body to produce insulin. Insulin is an anabolic hormone that works to build muscle. Carbohydrates trigger the body to make insulin, which decreases the amount of cortisol produced, therefore decreasing muscle breakdown.
The types of carbs you consume have an effect on this reaction. In general, you want to consume carbohydrates that are lower on the glycemic index (GI), like beans and whole grains, because since they take longer to digest, they do not cause an insulin spike. But following a workout, you should do the opposite by choosing carbs higher on the glycemic index, because they are more rapidly digested and therefore cause an increase in insulin production. High glycemic carbs include some breakfast cereals, rice, pasta, potatoes, pretzels and some fruits. Pairing these high-GI carbs with protein will provide the best post-workout snack.
• Salted pretzels with peanut butter
• Potato with plain yogurt
• Trail mix with cereal and nuts
• Fruit smoothie with milk
• String cheese and crackers
For best results, try to eat within 30 to 45 minutes following your workout.
Nutrient Timing: The Future of Sports Nutrition, by John Ivy and Robert Portman