Submitted to: North American Association for the Study of Obesity
Publication Type: Abstract Only
Publication Acceptance Date: 10/29/2000
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Children's ability to adapt to high fat diets may be a predisposing factor to obesity. We hypothesized that fat utilization would be negatively affected by body fat and intra-abdominal fat (IAF), and positively affected by fitness. Methods: We compared substrate utilization in 24 healthy, normal weight children, randomly assigned to isoenergetic diets with either rlow fat/high CHO (25/60% of energy) or high fat/low CHO (55/30% energy). W measured nonprotein RQ (NPRQ) and substrate utilization using 24-h calorimetry after a 7-d diet equilibration period. The effects of sex, puberty status (Tanner staging), body fat (DXA), intra-abdominal fat (MRI), and fitness (VO2 peak) on substrate utilization were tested. Data are presented as Mean+/-SD and were tested by repeated ANOVA. Substrate utilization is expressed as %NPEE. Results: Fuel utilization was not affected by puberty status (Tanner stages I vs. IV-V), body fat (8 to 24%), ,IAF (5 to 49 cm2), or fitness (0.8 to 4.1L/min). Adjusted for energy balance, NPRQ, CHO and fat utilization were significantly affected by diet (P=0.001) and sex (P=0.005). NPRQ (0.88-0.90) and CHO utilization (60.9- 68.7%) increased on the Low fat/high CHO diet. As expected, NPRQ (0.81- 0.85) decreased and fat utilization (49.4-65.4%) increased on the High fat/low CHO; however, changes in fuel utilization were less pronounced in girls than boys. Conclusion: Children adapt to high CHO and high fat diets, but the adaptive response is less complete on high fat diets in girls than boys.