CLINICAL TRIAL: DIETARY MACRONUTRIENT INTAKE AND EXERCISE ON GLUCOSE AND INSULIN

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 在过去的30年里，美国超重儿童（6-19岁）的患病率（BMI>第95百分位数）增加了3倍，1999年达到13-14%。随着儿童超重的增加，儿童（0-19岁）2型糖尿病的发病率增加了4倍。虽然肥胖相关的糖代谢障碍的病因是多因素的，但膳食大量营养素摄入和体力活动是潜在的重要因素。该建议的目的是在健康青少年中确定1）肥胖对能量消耗和底物氧化、由糖原生成和糖原分解产生的葡萄糖、胰岛素分泌和敏感性以及脂解的影响; 2）12周的适度运动计划是否会改善肥胖青少年的葡萄糖代谢，如果是，3）运动效果是否与肌细胞内脂肪含量的降低和/或脂质氧化的增加相关，以及4）饮食的膳食常量营养素组成是否影响运动的代谢效果。 为了解决这些问题，24超重（体脂>30%）和24名非肥胖者（体脂<26%）青少年将在三个场合进行研究（就在12周锻炼计划开始之前，进入计划的6周以及锻炼的最后一周期间）;在24名受试者（12名肥胖者和12名非肥胖者）中，三次研究中的每一次都将在7天高碳水化合物饮食之前进行，而在其他24名受试者中，将在7天高脂肪饮食之前进行。将使用最先进的稳定同位素-GCMS技术、MRI和24小时室内量热法获得实现上述目标所需的数据。这些研究提供的信息将提高我们对青少年肥胖代谢影响的理解，并将导致识别可能增加2型糖尿病风险或预防或延迟青少年2型糖尿病发展的因素。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Over the past 30 years the prevalence of overweight children (6-19 y) in the USA (BMI>95th percentile) has increased 3-fold to reach 13-14% in 1999. Concomitant with the increase in childhood overweight, the incidence of type 2 diabetes in children (0-19 y) has increased 4-fold. Although the etiology of obesity related impairment of glucose metabolism is multifactorial, dietary macronutrient intake and physical activity are potentially important factors. The aims of this proposal are to determine in healthy adolescents 1) the impact of obesity on energy expenditure and substrate oxidation, glucose production from gluconeogenesis and glycogenolysis, insulin secretion and sensitivity and lipolysis; 2) whether a 12 weeks moderate exercise program will improve glucose metabolism in obese adolescents, and if so, 3) whether the exercise effect is correlated with a decrease in intramyocellular fat content and/or increased lipid oxidation, and 4) whether dietary macronutrient composition of the diet impacts metabolic effects of exercise. To address these questions, 24 over weight (body fat >30%) and 24 non-obese (body fat <26%) adolescents will be studied on three occasions (just prior to the start of a 12 weeks exercise program, 6 weeks into the program and during the last week of exercise); in 24 subjects,12 obese and 12 non-obese, each of the three study occasions will be preceded by 7-d of a high carbohydrate diet, and in the other 24 of a 7-d high fat diet. State of the art stable isotope-GCMS techniques, MRI and 24 h room calorimetry will be used to obtain the data needed to address the aims stated above. The information provided by these studies will improve our understanding of the metabolic effects of obesity in adolescents and will lead to identifying factors, which may increase the risk of type 2 diabetes or prevent or delay the development of type 2 diabetes in adolescents.