TIME COURSE OP INCREASED LIPID AND GLUCOSE OXIDATION DURING THE EARLY PHASE OF CHILDHOOD OBESITY

To determine the time-course of metabolic dysfunctions in recent active obesity, we used indirect calorimetry in basal overnight conditions in 31 children (16M/15F) aged 11.9±0.4y with obesity duration 1-11y compared with 14 controls. Obese children produce 15% more energy than controls (p<.005), oxidize twice as much lipids (56±4 mg/min) than controls (25±5 mg/min, p<.0005), so that lipid oxidation provided 61±6% of overall energy production in the obese (33±3%in controls, p<.0005). Glucose oxidation was only 93±6 mg/min in the obese vs 136±6 mg/min in [he controls (p<.0005). The results were similar when normalized to body surface or lean body mass. While increased lipid oxidation was already present in the earlier stages of obesity, decreased glucose oxidation appeared only after =4 y of obesity, and worsened with obesity duration (r=0.72, p<.0005).