Insulin resistance in childhood obesity.

The prevalence of childhood obesity is on the rise in the USA. Approximately 20% of children and adolescents are overweight, as defined by a body mass index (BMI) greater than the 85th percentile. We describe a series of studies that has elucidated the impact of both childhood and adolescent obesity on glucose and lipid metabolism in vivo. We used magnetic resonance imaging to quantify the abdominal, visceral and subcutaneous fat depots, together with the insulin and glucose clamping techniques, to assess alterations in insulin action and secretion early in the course of obesity.