Colby S. Teeman1, Brooke J. Cull1, Stephanie P. Kurti2, Sam R. Emerson1, Mark D. Haub1 & Sara K. Rosenkranz1

1Department of Human Nutrition, 2Department of Kinesiology, Kansas State University, Manhattan, Kansas

Previous evidence suggests individuals with low resting fat oxidation rates may be more prone to the development of obesity and type 2 diabetes. Both exercise training and a high-fat diet are known to independently increase fat oxidation. It is currently unclear whether examining these two lifestyle factors simultaneously might moderate the resultant post-prandial (PP) fat oxidation. PUPROSE: The purpose of this study was to determine whether VO2peak moderates the association between dietary fat intake and PP fat oxidation following a high-fat meal. METHODS: Twenty-nine healthy young adults (17 M, aged 19-38 yrs) of varying aerobic capacities (VO2peak=49.4±11.1 ml/kg/min) were randomized to either a moderate-intensity walking (EX, energy expenditure 50% of breakfast kcals) or a sedentary condition. In the EX condition, walking was performed 60min PP. After an overnight fast, all participants consumed a high-fat breakfast (65% fat, 10 kcal/kgbw). Resting metabolic rate was assessed immediately after, and 200min following, consumption of the high-fat meal. Assessments included dietary fat via 3-day food log, VO2peak with a treadmill ramp protocol to exhaustion, indirect calorimetry with a ventilated hood system to determine fat oxidation at 0min and 200min PP, and %body fat via DEXA. RESULTS: Dietary fat intake was 798.6±235.4 kcal/day. Fat oxidation at baseline was not different from 200min PP (47.9±16.4 vs. 50.7±17.8 kcal/hr, p>0.05). There was a significant correlation between dietary fat intake and 200min PP fat oxidation (r=0.37, p2peak and 200min PP fat oxidation (r=0.62, p2peak on the association between dietary fat intake and PP fat oxidation revealed no significant moderation (ΔR2=0.007, p=0.60). A subsequent linear regression, including VO2peak, dietary fat intake,%body fat, baseline fat oxidation, and energy balance PP (kcals); predicted 79% of the variance in PP fat oxidation (adjusted R2= 0.79, pCONCLUSION: VO2peak did not moderate the association between dietary fat intake and PP fat oxidation. When examining additional factors thought to be associated with fat oxidation, however, 79% of the variance in PP fat oxidation could be explained. These results indicate that post-prandial fat oxidation is a complex process with multiple contributing factors.

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