Participants randomly receive first the standard meal at 8:00 am and the week after the standard meal at 8:00 pm or vice versa. Eight-h before the meal (respectively at 12:00 pm or at 12:00 am), the participants receive the same standard meal (without protein supplementation) at their home, and then are asked to spend in bed the following 6 hours. A 24-h urine collection is collected the day before each test in order to determine total urinary nitrogen excretion.