Intake of animal protein blend plus carbohydrate improves body composition with no impact on performance in endurance athletes

The impact of animal blend protein supplements in endurance athletes is scarcely researched. We investigated the effect of ingesting an admixture providing orange juice and protein from beef and whey versus carbohydrate alone on body composition and performance over a 10-week training period in male endurance athletes. Participants were randomly assigned to a protein (CHO+PRO, n=15) or a non-protein isoenergetic carbohydrate (CHO, n=15) group. Twenty grams of supplement mixed with orange juice was ingested post-workout or before breakfast on non-training days. Measurements were performed pre- and post-intervention on body composition (by dual-energy X-ray absorptiometry), peak oxygen consumption (VO2peak), and maximal aerobic speed (MAS). Twenty-five participants (CHO+PRO, n=12; CHO, n=13) completed the study. Only the CHO+PRO group significantly (p<0.05) reduced whole body fat (mean}SD) (-1.02 } 0.6 kg), total trunk fat (-0.81 } 0.9 kg) and increased total lower body lean mass (+0.52 } 0.7 kg), showing close to statistically significant increases of whole-body lean mass (+0.57 } 0.8 kg, p=0.055). Both groups reduced (p