Friday, September 25, 2009

Recovery from long distance: how about a bowl of cereal?

Over the past couple of decades, much work has come out of the Exercise Physiology and Metabolism Lab at the University of Texas at Austin. Much of this work has demonstrated the positive effects of combining protein and carbohydrate intake both during and following a long bout of exercise (a few hours, give or take). The merits of carbohydrate have been well known by athletes and scientists alike but its only been recently that the significant contributions of dietary protein for endurance performance and recovery have been investigated in well controlled studies.

The group at UT Austin has a new study out in the Journal of the International Society of Sports Nutrition (Kammer et al). They attempted to make this investigation more practical to athletes by testing the effects of eating a bowl of cereal with nonfat milk against a popular carbohydrate sport drink. Twelve cyclists and triathletes (8 men and 4 women) performed two 2-hr bouts of cycling at a moderately high intensity on separate days. Following the ride, they were provided either 40 oz of sport drink containing 78.5 grams of carbohydrate or a bowl of whole grain cereal and 1/3 liter of nonfat milk containing 59 grams of carbohydrate and 7.3 grams of protein. They were also give 3/4 liter of water on the cereal day to match the fluid amount of the sport drink.

The investigators measured muscle glycogen levels (biopsy needle method) immediately following exercise and again 1 hr later. They also measured blood glucose, insulin and lactate levels. Muscle tissue was also analyzed for proteins that are involved with glycogen and protein resynthesis through the effects of insulin.

What they found:
  • Insulin levels were higher during the 60-min recovery period during the cereal trial compare to the carbohydrate drink trial.
  • Glucose levels were similar between trials during the 1-hr recovery.
  • Glycogen resynthesis was similar between trials during the 1-hr recovery.
  • Muscle tissue proteins were similar between trials during the 1-hr recovery.

What does this mean for you? If you prefer cereal and milk following a long workout or race, go ahead and eat as long as you rehydrate as well. Cereal and milk are just as effective for glycogen replenishment as a sport drink. Another way to look at this is that the protein from the cereal and milk provides no additional benefits to glycogen resynthesis as long as the amount of carbohydrates is adequate. Practically speaking, it comes down to personal preference once again. As long as you consume adequate carbohydrate and protein following a long bout of exercise, you'll do just fine regardless of the source.

The recommended amount of carbohydrate or carbohydrate + protein following a glycogen depleting bout of exercise is 1.2 grams for every kilogram of body weight per hour. For a 150 lb person, that's about 80 grams of carbohydrate or 55 grams of carbohydrate + 25 grams of protein. For a 180 lb person, thats about 100 grams of carbohydrate or 65 grams carbohydrate + 35 grams protein.

For more information on protein-enhanced supplements go to my website: http://cmierphotoandfitness.net/protein.html

Reference: Kammer et al. Cereal and nonfat milk support muscle recovery following exercise. J. Inter. Soc. Sports Nutrition, 2009.

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