Effect of nopal on body weight gain, serum glucose and insulin concentrations. (A) Body weight gain of rats fed control diet (C) or high fat diet +5% sucrose in drinking 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, and HFS-C + N. (B) Fasting serum glucose and (D) insulin after the pretreatment and (C), (E) treatment periods respectively. Values are shown as means ± SEM, n = 5 rats per group. Statistical analysis of the pretreatment period was assessed by student t-test. Comparisons among groups after the treatment period were analyzed by two-way ANOVA followed by Fisher’s post-hoc test. Different letters indicate significant differences among groups, a > b > c > d, P < 0.05. Comparisons between 2 groups were analyzed by t-student test.