Associations of dietary sugar and glycemic index with adiposity and insulin dynamics in overweight Latino youth1–3

Background: Few studies have examined the relation between di-etary carbohydrate quality, adiposity, and insulin dynamics in chil-dren. Objective: The objective of the study was to determine which as-pects of dietary carbohydrate, specifically dietary sugar, fiber, gly-cemic index, or glycemic load, are associated with adiposity and insulin dynamics in overweight Latino children. Design: We examined 120 overweight Latino children (10–17 y old) with a family history of type 2 diabetes. Dietary intake was determined by repeated 24-h diet recalls. Adiposity was assessed by using total-body dual-energy X-ray absorptiometry. Insulin dynam-ics [insulin sensitivity (SI), acute insulin response, and disposition index (an index of!-cell function)] were measured by using a fre-quently sampled intravenous-glucose-tolerance test. Results: After adjustment for covariates, total sugar (g/d) was pos-itively correlated with body mass index (BMI; in kg/m2), BMI z scores, and total fat mass (r! 0.20, r! 0.22, and r! 21, respec-tively; P " 0.05) and negatively correlated with SI and disposition index (r!#0.29 and r!#0.24, respectively; P " 0.05). Dietary fiber, glycemic index, and glycemic load were not significantly correlated with adiposity or insulin dynamics before or after control for covariates. Regression analyses showed that total sugar intake explained an additional 3.4%, 4.6%, and 2.4 % of the variance in BMI, BMI z scores, and total fat mass, respectively, and an additional 5.6 % and 4.8 % of the variance in SI and disposition index (P"0.05), respectively, after control for covariates. Conclusion: In this cohort, total sugar intake, rather than glycemic index or glycemic load, was associated with higher adiposity mea-sures, lower SI, and lower measures of insulin secretion. Am