A 30-min basal calorimetric (Deltatrac II) exam is performed. Participants remain in a supine position but awake and motionless on a hospital bed during the whole period, except during the meal, when they can sit to eat. At 8:00 am (or pm), the participants consume the meal, and then rest in a supine position for 90 min. Then, a second 60 min-calorimetric evaluation is done. From the first calorimetric exam (the basal) until the end of the second (post-prandial) blood samples are drawn every 30 min. The same time schedule is adopted in the case of the morning meal (at 8:00 am) and the evening meal (at 8:00 pm).