Endurance training counteracts high-fat diet (*study)Posted by Anthony Roberts in Nutritional Companies & Supplements, Other | 0 comments
High-fat diets are far from optimal for endurance athletes. But what happens when you take a bunch of trained endurance athletes and give them a brief but absurdly high-fat (70% of calories) diet? As you might expect, their aerobic capability is hindered (probably due to glycogen being depleted), but it appears that their previous endurance training “protects” them from some of the bad effects seen in untrained men who eat a similar diet.
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Endurance exercise training blunts the deleterious effect of high-fat feeding on whole-body efficiency1. 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 [email protected] * 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.