The study involves 5 study days. The duration of the first 4 study days is approximately 6.5 hours per day and the duration of the 5th study day is approximately 8 hours. On each of the first 4 study days the effect a casein protein meal with or without leucine and carbohydrates will be examined. On the fifth study day the effect of 4 different levels of casein protein and carbohydrate intake by sip feeding (every 20 minutes) is examined.