Fig. 1. Study and experiments design. Experiments 1, 2 and 3 were based on controlled pure gas infusion, whereas experiment 4 used both gas infusion and methanol burns (Panel A). The in vivo experiment consisted of gas exchange measurements in young non-ventilated adults (Panel B, human study). EE: energy expenditure (in kcal/day); RER: respiratory exchange ratio; ICcE: Individual calibration control evaluation procedure. Time is presented either as minutes or hours. The metabolic carts used were the Q-NRG (Cosmed, Rome, Italy), the Vyntus CPX (Vyaire, Höchberg, Germany), the Omnical (Maastricht Instruments, Maastricht, The Netherlands), and the Ultima CardiO2 (Medgraphics Corporation, St. Paul, MN, USA).