The ingestion of fructose, particularly in refined form, has significantly increased in the North American diet over the last two decades. The unique way in which fructose is metabolized has given rise to much research examining whether fructose is advantageous in appetite control, exercise endurance, and disease states such as diabetes. Overall, there is very little evidence that modest amounts of fructose have detrimental effects on carbohydrate and lipid metabolism in nondiabetic or NIDDM subjects or that its use is particularly advantageous compared to that of other sugars. However, fructose can cause insulin and triglyceride levels to rise dramatically, and hence be potentially harmful, in a subgroup of NIDDM subjects who have concomitant pronounced hypertriglyceridemia. Large doses of fructose should also be avoided by subjects with gout because of the hyperuricemia which may result. No evidence exists that fructose has any clear advantages over glucose in regard to exercise endurance. Similarly there is no conclusive evidence that physiologic amounts of dietary fructose exacerbate copper deficiency or aid in weight control.

To determine whether differences in the metabolic response to two common starches could be eliminated by altering the physical form of food, 12 normal and 6 noninsulin-dependent diabetic (NIDDM) subjects were studied after consumption of test loads of whole and blended rice and potato. In normal and NIDDM subjects the lower postprandial glycemia and insulinemia of whole rice was eliminated and became similar to that of whole potato, which was unaffected by blending. The glucagon responses were unchanged and similar in both groups under all study conditions. In both normal and NIDDM subjects the glucose and insulin response to a particular starch is not a stable feature dependent on the unique characteristics of the starch molecule but is affected by food processing and the form in which it is presented to the gastrointestinal tract.

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