 REE and DIT are measured by indirect calorimetry . The device used is a using an open-circuit ventilated hood system QUARK RMR, Cosmed, Pavona; Italy. The respiration quo- tient RQ and flow settings are calibrated by reference to alcohol combustion every six months. Before each test, the calorimeter is calibrated with a reference gas mixture 5 CO2, 95 O2 vv. Expired carbon di- oxide VCO2 and inspired oxygen VO2 -flows are recorded, as well as the RQ. EE is calculated every minute from oxygen consumption VO2 in mlmin and carbon dioxide production VCO2 in mlmin using the Weir formula without protein correction. DIT is measured during 6 hours after a calibrated breakfast normal fat diet or high fat diet according to the cross-over design as 30 of theoric energy intake. 