The protein requirements of athletes is approximately 1.2 - 1.8 g/kg body weight, compared with 0.8 - 0.9 g/kg body weight for less active individuals. For heavy athletes this extra requirement is especially important. Muscle mass is increased by the rate of anabolism and destroyed by the rate of catabolism during exercise. The whey protein in Nutrisport 90+ Protein is absorbed quickly, having a very high biological value and an anabolic effect that lasts a couple of hours. The Micellar Casein in 90+ Protein is absorbed much more slowly, giving a sustained anti-catabolic action. It has therefore been recommended to take Whey Protein Isolate in the morning, and Micellar Casein but not any denatured casein last thing at night. So Nutrisport 90+ provides the best of both for muscle growth at any time of the day or night.