Tolerance tests using glucose, sucrose, fructose, or sorbitol each at 4 dose levels, were carried out in nine healthy young men and during the 90 min after ingestion the plasma serum concentrations of glucose, insulin, fructose, triglyceride, glycerol, uric acid, lactate, and pyruvate were estimated. It was confirmed that serum glucose levels are unaffected by the amount of glucose given. Little ... [Show full abstract] fructose seems to be converted to glucose judging by the serum fructose levels following sucrose and fructose, and by the small insulin response to oral fructose. The insulin response to a sucrose meal is half of that after an equivalent amount of glucose. The fall in serum triglyceride seen after carbohydrate meals is not related to insulin. Only glucose is not associated with a rise in serum uric acid, lactate, and pyruvate concentrations after ingestion.