This is a revised competing renewal of a grant whose overall historical goal has been to examine the determinants of insulin resistance in children, especially the role of total fat and visceral fat during pubertal development in """"""""high risk"""""""" minority children. The overall objective of this renewal is to conduct a randomized controlled study to examine the effects of 16-week exercise and diet interventions on insulin sensitivity, insulin secretion and body fat distribution in overweight Hispanic boys and girls (n=80). Subjects will be randomized to: A) Control; B) Strength training; C) Modification of carbohydrate intake; or, D) Strength training + modification of carbohydrate intake. The primary outcomes will include detailed measures at the level of body composition (total lean and fat mass, visceral fat, intramyocellular fat and liver fat) and insulin/glucose regulation (insulin secretion & sensitivity). The hypotheses are: 1) Both interventions will have separate and independent effects on improving insulin resistance; 2) Strength training will improve insulin resistance by re-distribution of body fat (lower visceral fat, intramyocellular lipid and liver fat); 3) Carbohydrate modification will improve insulin resistance and beta-cell function by reducing insulin secretion; and, 4) These effects will be independent of any effects of either intervention on weight loss or loss in whole body fat. We focus on Hispanic children because they are an understudied high-risk population, and they display significant obesity related metabolic abnormalities probably emanating from profound insulin resistance. If our hypotheses are borne out, it will provide evidence for the incorporation of more specific dietary recommendations and strength training in the prevention and management of obesity, type 2 diabetes and cardiovascular risk in overweight Hispanic youth.
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