ACUTE EFFECTS ON INSULIN SENSITIVITY AND DIURNAL METABOLIC PROFILES OF A HIGH-SUCROSE COMPARED WITH A HIGH-STARCH DIET

Decreased insulin sensitivity is associated with diabetes mellitus, is chemic heart disease, and hypertension, both independently and in asso ciation as what is called the metabolic syndrome. Although the negativ e effects of obesity, sedentary lifestyles, and high-fat diets on insu lin sensitivity are well established, the influence of type and quanti ty of dietary carbohydrate is more controversial. This study aimed to assess the acute (24 h) effects of a high-sucrose compared with a high -starch diet on insulin sensitivity and to identify changes in blood m etabolites that might lead to altered insulin sensitivity. Eight healt hy adults consumed high-sucrose or high-starch diets (50% of dietary e nergy) in a randomized, crossover trial. Insulin sensitivity was asses sed by a short insulin tolerance test the following morning. No differ ences were detected in insulin sensitivity, either for glucose metabol ism [Kitt(glucose) (the rate constant for the decline in blood glucose concentrations) for sucrose diet = 3.86 %/min, for starch diet = 3.72 %/min: pooled SEM = 0.23] or for lipid metabolism [Kitt(NEFA) (the rat e constant for the decline in blood fatty acid concentrations) for suc rose diet = 12.9%/min, for starch diet = 11.4%/min; pooled SEM = 1.18] . Profiles for blood glucose and serum insulin concentrations revealed higher peaks and lower troughs with the high-sucrose diet whereas are a under the curve for glucose was higher with the high-starch diet (67 80 +/- 245 mmol.L/min) than with the high-sucrose diet (6290 +/- 283 m mol.L/min) (P< 0.001). Plasma fatty acid concentrations showed a late postprandial rise with the sucrose-rich diet relative to the starch-ri ch diet, which was mirrored with a fractionally later peak in triacylg lycerol concentrations.