In relation to human studies, those involving laboratory
animals have the advantage of providing information
on the mechanisms and effects resulting from
chronic consumption of low or high GI diets, as well as
greater control over possible interfering factors.
In one of these crossover studies, the effect of
ingesting diets with differing GI was assessed in adult
rats for 32 weeks. Consumption of the GI-rich diet
resulted in two times greater visceral fat, even after
adjustment for total body fat. Contrarily, the subcutaneous
adipose tissue did not differ between groups
after adjustment for total fat. Lower levels of fat oxidation
were observed in the high-GI group.59
Furthermore, in C5BL/6 mice the effect of high or
low GI diets was evaluated for 16 weeks, presenting
high or low fat content. It was found that the postprandial
glycemic response was greater in the high GI diet,
independent of fat content. Although body weight did
not differ between groups, mice fed a hypolipidic diet
with high GL showed much higher adiposity than those
fed a low-fat diet with low GI.11