Body weight and composition in laboratory rats: effects of diets with high or low protein concentrations.

Adult rats fed high concentrations of dietary protein for 9 weeks gained more weight than rats fed isoenergetic diets containing less protein. There were no significant differences in tail and body lengths among several groups of rats on diets containing different amounts of protein; however, total body fat was significantly greater in the rats fed on diets containing 25 percent protein compared to the rats fed 5 percent protein diets. These findings suggest that the role of dietary protein in obesity and other conditions deserves further scrutiny.