Differences in responses of male and female rats to dietary carbohydrate-fat combinations

Abstract

Male and female rats were fed diets containing different carbohydrate-fat combinations for 2, 4, and 6 weeks to determine whether changes in tissue lipids would be similar in female and male rats. Starch and sucrose were each fed with low and high levels (15% and 40% of energy) of safflower oil (SAFF) and beef tallow (BT). In general, females appeared to adapt to dietary changes more readily than males, showing less extreme changes in level and composition of liver lipids. Major sex related differences were that female rats had: (a) an absence of progressive accumulation of total liver lipid, linoleic acid, and cholesterol when fed the starch-high SAFF diet; (b) a lack of significant effect of the sucrose-low BT combination, as compared with starch-low BT, on amount and fatty acid composition of liver lipid; and (c) higher percentages of stearic acid in liver lipids. Results demonstrated the fallacy of assuming that metabolic effects of dietary constituents observed in males will be the same in females, and vice versa.