ArticlesClinical Investigation nature publishing group BACKGROUND: A low-glycemic index (GI) diet may be beneficial for weight management due to its effect on insulin metabolism and satiety. METHODS: Obese children aged 9-16 y were randomly assigned either a low-GI diet or a low-fat diet (control group) for 6 mo. Body composition changes were measured by dualenergy X-ray absorptiometry and bioelectrical impedance analysis. Insulin sensitivity was measured by fasting plasma glucose and insulin. RESULTS: Fifty-two participants completed the study (mean age: 12.0 ± 2.0 y, 35 boys); both groups showed significantly decreased BMI z-score but similar changes in fat and fat-free mass. The low-GI group demonstrated a significant decline in fasting plasma insulin (22.2 ± 14.3 to 13.7 ± 10.9 mU/l; P = 0.004) and homeostatic model of assessment-insulin resistance (4.8 ± 3.3 to 2.9 ± 2.3; P = 0.007), whereas the control group did not. However, general linear model showed no significant difference in insulin resistance between groups after adjusting for baseline levels, suggesting that the greater reduction in insulin resistance in the low-GI group may be explained by higher baseline values. CONCLUSION: Despite subtle effects on body composition, a low-GI diet may improve insulin sensitivity in obese children with high baseline insulin. A bigger study in obese children with insulin resistance could be worthwhile to confirm our findings.C urrently, the prevalence of childhood obesity has been increasing worldwide (1). The Centers for Disease Control and Prevention reported that about 17% of children and adolescents in the United States aged 2-19 y were obese (2). Furthermore, the prevalence of the metabolic syndrome has been rapidly rising in obese children, and with it, the risk of cardiovascular disease (3). About 60% of overweight children have at least one cardiovascular disease risk factors such as hypertension, dyslipidemia, and insulin resistance. In addition, more than 25% of them have more than one type of cardiovascular disease risk factors (1). The common complications of childhood obesity are the metabolic syndrome (hypertension, dyslipidemia, insulin resistance, and type 2 diabetes), obstructive sleep apnea, nonalcoholic steatohepatitis, polycystic ovary syndrome, orthopedic complications, and premature atherosclerosis (4).At present, we are unable to describe the exact etiology of obesity, but one of the most common causes is an imbalance between energy intake and physical activity. Treatment of obesity is difficult and can be done by several approaches, including dietary control (such as low-fat, low-energy diet), physical activity program, behavioral modification (such as generating weight reduction goal, self-monitoring, as well as positive reinforcement by parents), and medical treatment. There are many pediatric patients seeking hospital-based obesity treatment. Most of them have one or more of the complications of obesity mentioned above as well as a loss of their self-esteem and social lives. In general, ...

Background The glycemic index (GI) reflects body responses to different carbohydrate-rich foods. Generally, it cannot be simply predicted from the composition of the food but needs in vivo testing. Methods Healthy adult volunteers with normal body mass index were recruited. Each volunteer was asked to participate in the study center twice in the first week to consume the reference glucose (50 g) and once a week thereafter to consume the study fruit juices in a random order. The study fruit juices were Florida orange juice, Tangerine orange juice, Blackcurrant mixed juice, and Veggie V9 orange carrot juice which were already available on the market. The serving size of each fruit juice was calculated to provide 50 g of glycemic carbohydrate. The fasting and subsequent venous blood samplings were obtained through the indwelling venous catheters at 0, 15, 30, 45, 60, 90, and 120 min after the test drink consumption and immediately sent for plasma glucose and insulin. GI and insulin indices were calculated from the incremental area under the curve of postprandial glucose of the test drink divided by the reference drink. Glycemic load (GL) was calculated from the GI multiplied by carbohydrate content in the serving size. Results A total of 12 volunteers participated in the study. Plasma glucose and insulin peaked at 30 min after the drink was consumed, and then started to decline at 120 min. Tangerine orange juice had the lowest GI (34.1 ± 18.7) and GL (8.1 g). Veggie V9 had the highest GI (69.6 ± 43.3) but it was in the third GL rank (12.4 g). The insulin responses correlated well with the GI. Fructose to glucose ratio was inversely associated with GI and insulin responses for all study fruit juices. Fiber contents in the study juices did not correlate with glycemic and insulin indices. Conclusions The GIs of fruit juices were varied but consistently showed a positive correlation with insulin indices. Fruit juices with low GI are a healthier choice for people with diabetes as well as individuals who want to stay healthy since it produces more subtle postprandial glucose and insulin responses.