Dietary fat and adiposity: a dose-response relationship in adult male rats fed isocalorically.

This study examined the effects of increasing levels of dietary fat fed isocalorically on body weight, body composition, and adipose distribution. Adult male rats were weight matched into four groups. One group that was fed a low-fat diet (12%) served as reference controls. The other three groups were fed diets of 24, 36, or 48% fat in amounts to equal the energy intake of the control group. After 6 wk, body weights of the four groups were not significantly different. Intrascapular brown fat did not differ between groups. Total body fat and adipose depot weights, however, increased in proportion to the level of fat in the diet. Total body fat and retroperitoneal and mesenteric depot weights of the 48% fat group were greater than controls (P < 0.05). Mesenteric fat in this group was also significantly increased over all other groups (P < 0.05). These results show that high-fat diets fed to adult animals cause increased body fat in the absence of significant changes in body weight and that mesenteric fat is increased disproportionately.