Deleterious effects of a cafeteria diet on the livers of nonobese rats

Rats were fed from weaning on 1 of 3 diets. Those fed a cafeteria diet had livers that were enlarged and abnormal by visual inspection. The rats themselves appeared healthy, had a normal growth rate, and were not significantly different in weight from control animals. Histologic examination revealed the livers of these rats to be rich in lipids and glycogen. Liver function tests showed a depressed level of alanine transaminase and an abnormal high-density lipoprotein/low-density lipoprotein. Dietary lipids generate free radicals that can interact with, and damage, DNA. However, when DNA was extracted from the livers and examined for the presence of the adduct M1-dG, there were no significant differences in adduct levels in livers from animals fed any of the diets. We conclude that the cafeteria diet can have long-term adverse effects on liver function even though overt measures of health may be unimpaired, body mass is maintained within normal limits, and liver DNA is not adversely affected.