Weight gain during the 20 weeks of high fat diet administration was measured among AA (■, N = 14 males and 14 females), RA (▨, N = 6 males) and RR (□, N = 7 males and 6 females) mice (A). During the initial week of high fat diet administration, exercise wheels were placed into the cages to record voluntary activity (B). By indirect calorimetry, resting oxygen consumption (C) and respiratory quotient (D) were then determined. *p<0.05 and ** p<0.01 versus AA