In 2008, David Rowlands, PhD, senior lecturer with the Institute of Food, Nutrition, and Human Health at Massey University in New Zealand, published a study showing that male cyclists who ingested protein and carbohydrates between intense training bouts gained distinct performance and postexercise recovery advantages over men who fueled only with carbohydrates (Applied Physiology, Nutrition, and Metabolism, 33 , 39–51).
When the study came out, women cyclists contacted him asking to be included in any further research. The results of his follow-up study were published online in May in Medicine & Science in Sports & Exercise and are a good reminder that what’s good for Adam isn’t always good for Eve.
Rowlands and a colleague set out to determine whether there was a meaningful difference between high- versus low-protein recovery diets on subsequent performance in well-trained female cyclists. Surprisingly, the findings were directly opposite those of the male study.
The female subjects not only did not benefit from protein during recovery, but they rated their leg fatigue and soreness as more intense than those of the women who ingested only carbohydrate. In addition, and unlike the men, they could not ride longer or with more intensity than the carb-only group. In the high-protein condition, plasma-glucose concentrations were lower during recovery, and plasma-lactate concentrations were lower during the sprints.
Yet another interesting finding was that the effects on circulating creatine-kinase (a biochemical marker of muscle tissue trauma) activity were trivial, which suggests that muscle damage was kept to a minimum. In the original study the males showed higher creatine-kinase activity during the hard intervals.
Rowlands concluded that “in contrast with previous findings in males, we observed no clear influence of dietary protein quantity on subsequent performance in females. The nitrogen balance findings suggest that female cyclists training intensely have daily protein requirements approximately 1.6 times the recommended daily allowance, but 0.65 times that of males.” Since the study was one-of-a-kind, it will need to be replicated.
Read the abstract of this study at http://journals.lww.com/acsm-msse/Abstract/publishahead/Effect_of_High_Protein_Feeding_on_Performance_and.99180.aspx.