National Nutrition Month: Replenishing nutrients lost during exercise
February 25, 2011
The old saying "you are what you eat" was popularized (but not originated) by an English nutritionist named Dr. Victor Lindlahr who published a book in the 1940s called "You Are What You Eat: How to Win and Keep Health with Diet."
Lindlahr was a strong believer in the idea that food controls health. The last 70 years of nutrition research has provided ample evidence that Lindlahr was right-good nutrition has a profound positive influence on our health. We also now understand how important "recovery" nutrition is for athletes and how it plays a role in the prevention of injury.
Strenuous exercise such as endurance running, sprinting, or resistance training deplete energy (muscle glycogen stores) and cause muscle damage. If depleted energy is not replaced and muscle damage not repaired adequately, injury and reduced physical performance will occur. Studies of women who exercise show a negative energy balance is a risk factor for stress fractures of the bone. While both civilian and military research have proven that consuming foods that restore energy balance overcomes fatigue, minimizes muscle damage, promotes recovery and protects against heat injury, the timing of the nutritional intervention is critical.
Research shows that consuming a combination of carbohydrates and protein within a 60-minute window immediately following very strenuous exercise initiates repair of muscles damaged during the activity and begins the replenishment of muscle energy stores. In fact this is the only recommendation from the Joint Physical Training Injury Prevention Work Group related to nutrition and its effect in the prevention of musculoskeletal injury. During this time, the body is primed for rebuilding what was used or broken down during the exercise. If the nutrients are consumed more than 60 minutes after the end of the exercise bout, the body is less able to absorb the nutrients, thus diminishing the rate of recovery.
After an hour of exercise, the ideal balance of nutrients needed to allow for the most rapid replenishment of muscle glycogen to optimize and accelerate the recovery process is roughly 12 to 18 grams of protein and 50 to 75 grams of carbohydrate (a ratio of 1 gram of protein for every 4 grams of carbohydrate).