Effect of nopal on Energy expenditure and energy intake. (A) O2 consumption, (C) respiratory exchange ratio of Wistar rats fed a control diet or a high fat diet +5% sucrose in drinking water. water (HFS) during 7 months (pretreatment period). After this period, obese rats were switched to one of the experimental diets for 1 month (treatment period): HFS, HFS + N, HFS-C, HFS-C + N; (B), (D). Food intake, water consumption and energy intake in all the experimental groups. Values are shown as means ± SEM, n = 5 rats per group. Comparisons among groups were analyzed by two-way ANOVA. Comparisons between 2 groups were analyzed by student t test.