Adipose cell size and glucose tolerance in obese children and effects of diet.

Adipose cell size and the glucose and insulin response to an oral glucose load have been studied in 26 obese children. Adipose cells were found to be enlarged, and hyperinsulinaemia was demonstrated both in the fasting state and also after oral glucose. The degree of hyperinsulinaemia could not be predicted by adipose cell size. In 14 children studies were repeated after a period of weight loss. A marked fall in fasting serum insulin occurred in all children over the first week of treatment. A reduction in adipose cell size was demonstrated over a longer period, but there was no change in the total number of adipose cells. In 7 children who were still losing weight when a second glucose tolerance test was performed, insulin levels after oral glucose were reduced, but there was no reduction in insulin levels in 7 children studied after they had stopped losing weight. The reduction in body fat and adipose cell size in these two groups of children was no different. Thus it was not possible to predict the fall in insulin levels from changes in body composition or adipose cell size. These data do not support the hypothesis of a direct causal relation between the increase in adipose cell size and the hyperinsulinaemia of obesity.