Potential participants will meet us for a preliminary assessment where we will evaluate their eligibility to participate in the study. The preliminary assessment will take approximately 1 hour during which we will examine body composition (Bioelectrical impedance, skin-fold measurements, height and weight), resting energy expenditure (by indirect calorimetry) and medical history (questionnaire). We will collect a 3 day food diary, to determine usual food intake and food preferences. Based on the 3 day food record we will prescribe a standardized diet two days prior to the study day to ensure protein intake of 1.5 g/kg/day and 1.7 x resting energy.