Weight Reduction in Young Obese Children. I. Effects on Adipose Tissue Cellularity and Metabolism

Abstract

SummaryA 10-year longitudinal study was conducted on 26 prepubescent youngsters who had undergone successful weight reduction. Their ages ranged from 2 to 10 years when the study began. In all subjects, weight reduction proceeded only by a decrease in adipose cell size (from 0.62 + 0.02 to 0.46 k 0.02 pg lipid per cell) and resulted in a corresponding 33% decrease (from 177 + 6 to 144 + 5%) in percent ideal body weights. Cell numbers did not change appreciably during the period of weight loss (29.4 k 2.6 versus 28.7 k 2.3 x lo9 total adipocytes). Three years after the start of the study, 14 of 20 youngsters had maintained their reduced percent ideal body weights, including eight who remained below 130% ideal body weight. Ten years later, only four remained below 130% ideal body weight. All four children had total adipose cell numbers below 20 x lo9 total adipocytes at the start of the weight reduction program, a value below the lower limit for adult normal weight subjects. Thirteen other children have maintained or decreased their initial percent ideal weights. The remaining nine youngsters have further increased their percent ideal body weights. In vitro metabolic studies of the patient's adipocytes revealed a >50% changes in glucose tolerance, serum insulin concentrations, and numbers and/or affinity of the cell membrane insulin receptors (17,37,46). Adipocytes in obese adolescents also display diminished in vitro epinephrine responsivity pre-and immediately postweight reduction (28). Previous experiments in animals have shown that significant reductions in total adult adipose cell number can only be permanently achieved by altering early nutritional intake or by increasing early exercise patterns (26,30,39). Thus, it is important to assess if a similar situation in young children exists to determine critical periods for fat cell development. The present investigation was designed to measure adipose cell number, size, in vitro responsiveness of adipocytes to insulin and epinephrine, plus the percent ideal weight in young obese children pre-and postweight reduction to assess the relative importance of these parameters on the ability to permanently maintain the reduced state. MATERIALS AND METHODS SUBJECTSdepression of epinephrine-stimulated lipolysis pre-and immediately postweight reduction; this decrease persisted for the entire Twenty-six prepubescent children, 12 boys and 14 girls, ages 2 period of study, irrespective of the maintenance of a normal to 10 years at the start of the study, were investigated. They were perfent ideal body weight. At the same time, normal 150% in-originally referred to our Pediatric Nutrition Clinic because of creases in the in vitro production of 1 4~0~ from ,l-~~Clglucose in obvious and significant obesity which was documented before the presence of insulin occurred. their first birthday. All were tested and examined to exclude the concomitant presence of described endocrinopathies. They were then placed, as outpatients, on weight reduction diets calculated Speculation at approx...

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