Friday, April 18, 2014

Exercise-related temporal variation of macro-nutrient balance

Last Updated Dec 2007


Q: Are you familiar with the book "Nutrient Timing" by John Ivy and Robert Portman, which focuses on sports nutrition? They are advocating an average macronutrient balance that is approximately 23(P):44(C):33(F), but they also advocate varying that ratio in relation to the daily workout. During exercise, it is 1:4:0. In the 45-minute window after exercise, it is 1:3:0. In the two to four-hour period after exercise, the carbs go down and the fats go up, and during the rest of the day the balance shifts so that the overall ratio of 23:44:33 is maintained. They claim, based on cited research results, that during and after exercise, the high GI intake goes to muscle glycogen and muscle building, while during the more sedentary portions of the day, any high GI intake would go directly to fat store, which, of course, you would want to avoid. So essentially, they go high carb, low fat during and post exercise and then low carb during sedentary portions of day. What do think?

I have seven years of being very active (20 to 50 miles running per week, zone experience, and I average something like a 25:40:35 macro-nutrient balance.
 
A: I am very familiar with John Ivy’s research. He only looked at a 1:4 ratio of protein to carbohydrate in the post-recovery phase. My research with Olympic athletes indicates that a 2:3 ratio works even better because of the impact on key enzymes, such as AMP kinase, and genetic transcription elements, such as mTOR. The key for recovery lies in the hormonal changes induced by the ratio. It is even more important in the 20-22-hour regeneration phase that takes place after intense exercise in which muscle damage is repaired. Maintaining a constant balance of protein, carbohydrate and fat as you have enables the body to adapt its enzyme balance to maximize ATP production with the least number of incoming calories.    
 
 
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