Endurance exercise training blunts the deleterious effect of high-fat feeding on whole-body efficiency
1. Lindsay Martin Edwards1,*, 2. Cameron J Holloway2, 3. Andrew James Murray3, 4. Nicholas S Knight2, 5. Emma E Carter2, 6. Graham J. Kemp4, 7. Campbell H Thompson5, 8. Damian J Tyler2, 9. Stefan Neubauer2, 10. Peter A. Robbins2, and 11. Kieran Clarke2 + Author Affiliations 1. 1University of Tasmania 2. 2University of Oxford 3. 3Cambridge University 4. 4University of Liverpool 5. 5Flinders University of South Australia 1. *↵ University of Tasmania
l.m.edwards@utas.edu.au * Submitted 3 January 2011. * Revision received 5 May 2011. * accepted in final form 26 May 2011.
Abstract We recently showed that a week-long high-fat diet reduced whole-body exercise efficiency in sedentary men by > 10%. To test if a similar dietary regime would blunt whole-body efficiency in trained men and, as a consequence, hinder aerobic exercise performance, sixteen trained men were given a short-term high fat (70% kcal from fat) and a moderate carbohydrate (50% kcal from carbohydrate) diet (MCD), in random order. Efficiency was assessed during a standardised exercise task on a cycle ergometer, with aerobic performance assessed during a one-hour time trial and mitochondrial function later measured using 31P-magnetic resonance spectroscopy. The subjects then underwent a two-week wash-out period, before the study was repeated with the diets crossed-over. Muscle biopsies, for mitochondrial protein analysis, were taken at the start of the study and on the fifth day of each diet. Plasma fatty acids were 60% higher on the high-fat diet (HFD) compared with MCD (p < 0.05). However, there was no change in whole-body efficiency and no change in mitochondrial function. Endurance exercise performance was significantly reduced (p < 0.01), most probably due to glycogen depletion. Neither diet led to changes in citrate synthase, ATP-synthase or the mitochondrial uncoupling protein (UCP3). We conclude that prior exercise training blunts the deleterious effect of short-term high-fat feeding on whole-body efficiency.