Protocol design outline with an example subject. (a) Study timeline. (b) Representative example of 1 day in the room calorimeter showing EE (black) and motion (blue), including two resting measurement periods (shaded). (c) The Scholander plot is used to determine BMR, CIT, T_lc, and insulation (inverse of the slope of the heat requirement). The set point for T_core is where the heat requirement line intersects the T_a axis. The thermoneutral zone starts at the T_lc. Data (black circles) obtained from one lean subject and analyzed by branch-chain regression (blue lines) are included as an example.