(A) diagram of cage placement on warm water blankets. Each cage is housed half on, and half off, the blanket. (B) Temperatures of the blanket surface, the bottom of the warmed cage, and the bottom of cages housed at ambient vivarium temperature, measured with an infrared thermometer. The red box indicates the mouse thermoneutral zone. (C) Body mass of LFLS and HFHS Rag1-null females. The vertical line indicates the initiation of thermoneutral housing; N=16 per group. (D) Body fat percentage, (E) Fat mass, and (F) lean mass measured before (pre) and after (post) warming with qMR in mice fed LFLS or HFHS diets; N=16 per group. Data were analyzed by 2-way ANOVA testing for main effects of diet or time (panel c) or diet and warming (panels d-f) and for an interaction.