Weanling rats were given diets containing a high proportion of either glucose, sucrose or fructose until they reached 200 g weight, when they were either transferred to a control (chow) diet for 4 weeks or killed. The results were compared with rats receiving a control diet throughout. The triglyceride (TG) and cholesterol levels in liver and in serum had returned to values similar to the control animals 4 weeks after being given the control diet. The fatty acid profile of liver TG and adipose lipid tended to take longer to return to normal.