Bret Goodpaster, Ph.D., is an exercise physiologist and metabolism researcher at Sanford Burnham Prebys Medical Discovery Institute (SBP) and the Translational Research Institute for Metabolism and Diabetes (TRI-MD) in Orlando, Fla. An expert in the area of muscle function and exercise, Dr. Goodpaster has science-based advice on what to eat and drink to achieve peak performance and the truth behind misconceptions about the ideal fuel for sport. Get this -- he was a competitive road cyclist for 25 years and now does triathlons. Q: Should you eat differently during training versus competition day? Dr. Goodpaster: What you eat on the day of an endurance event like running or cycling is incredibly important. Metabolic research has proven that consuming carbohydrates before and during an event can dramatically influence performance. For training lasting one to two hours, the body has plenty of stored fat or carbohydrates so it’s unnecessary to drink or eat additional calories, and consuming extra calories could blunt the body’s adaptation to better use fat. Q: Do nutritional needs vary by age or by fitness level? Dr. Goodpaster: Whether you are a Master’s level swimmer or a young Olympian, nutritional needs are more dependent on fitness and exercise. As you age there will be some muscle loss, so overall calorie needs aren’t as high but exercise may slow some aspects of the aging process such as decreased BMI and muscle loss. Daily nutritional needs are determined by fitness level, body composition (lean to muscle ratio) and exercise level regardless of age. Q: Low-carb diets are becoming more popular. Should athletes jump on the bandwagon? Dr. Goodpaster: Low carbohydrate diets are a risky choice for athletes. We’ve known since the 1930’s that carbohydrates increase endurance performance. Extrapolating low carb, weight loss diets to athletic performance doesn’t hold water. However, during training, it may be okay to somewhat reduce carbohydrates in a healthy diet as it may help train the body to burn fat more efficiently. Bottom line —right before or during competition, don’t limit carbohydrates as an important fuel source. Is water really the best way to stay hydrated? Dr. Goodpaster: NO! Years of research show that water alone is not the best way to hydrate or rehydrate during strenuous exercise. Typically, it’s best to consume electrolyte drinks during and after an event or training session. Fluids consumed during exercise won’t be sufficient to completely replace what is lost through sweat so drinking extra fluids afterwards is important and can reduce or prevent the side effects of electrolyte loss such as cramping and fatigue. What is the best source of energy for muscle endurance? Dr. Goodpaster: The more you rely on stored fat and save valuable carbohydrate depots, the better. Classic training improves the body’s use of fat stored in muscle and adipose tissue. As you exercise at a low to moderate intensity the body will preferentially burn fat for energy; as exercise intensity increases, the body converts to burning more carbohydrate. With just a few thousand calories of carbohydrate stored in body reserves, endurance athletes will ultimately shift back to fat for energy, however fat isn’t converted as quickly, so marathoners can “hit the wall.” Dr. Goodpaster is available for interviews. Call Deborah Robison at (407) 745-2092 About Dr. Goodpaster: Dr. Goodpaster is Senior Investigator at the Translational Research Institute for Metabolism and Diabetes (TRI-MD), and Professor at the Sanford Burnham Prebys Medical Discovery Institute (SBP). Dr. Goodpaster’s research focus includes exercise physiology, metabolism, obesity, diabetes and aging. His primary research has been the clinical translational ‘bench to bedside’ study of skeletal muscle and its role in human health, aging and disease. A major thrust of Dr. Goodpaster’s research program is to better understand how exercise impacts physiological, molecular and biochemical pathways in obesity and during weight loss. For more information, please visit: