Prof Stephen Phinney on the science behind low carb diets for athletes: A rational approach

Consider the classic understanding that high carbohydrate intakes are necessary for optimal endurance performance. What if that failed to take into account the physiological changes that occur with adaptation to low carbohydrate diets? In this podcast, @JohannWindt interviews physician-researcher Dr. Stephen Phinney about his last 30 years of research into low-carb ketogenic diets. Highlights include the previously undocumented levels of during exercise fat oxidation seen in endurance athletes adapted to a low carbohydrate diet. He also touches on ketogenic diets’ potential benefits in other sporting contexts, addresses common criticisms, and looks ahead to future research questions in the field. Further reading and papers discussed in the podcast are included below. Vermont and MIT Study Dr. Phinney’s original two studies on low carbohydrate performance. Original two low carb performance studies. http://www.metabolismjournal.com/article/0026-0495%2883%2990105-1/abstract http://www.ncbi.nlm.nih.gov/pmc/articles/PMC371554/ Phinney SD et al. The human metabolic response to chronic ketosis without caloric restriction: physical and biochemical adaptation. Metabolism 1983;32:757-68. http://www.metabolismjournal.com/article/0026-0495%2883%2990105-1/abstract Phinney SD et al. capacity for moderate exercise in obese subjects after adaptation to a hypocaloric, ketogenic diet. J Clin Invest 1980;66:1152-61. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC371554/ The gymnast study mentioned in the podcast: Paoli et al. Ketogenic diet does not affect strength performance in elite artistic gymnasts. J Int Soc Sports Nutr 2012; 9: 34. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3411406/ Significant decrease in inflammation shown in low carb diets by Forsythe, Phinney, et al.Comparison of low fat and low carbohydrate diets on circulating fatty acid composition and markers of inflammation. Lipids 2008;43:65-77. http://link.springer.com/article/10.1007/s11745-007-3132-7?no-access=true Prof Phinney’s recent BJSM Editorial: Noakes T, Volek JS, Phinney SD. Low-carbohydrate diet for athletes: what evidence? Br J Sports Med 2014 http://bjsm.bmj.com/content/early/2014/05/26/bjsports-2014-093824.extract Prof Phinney and Volek’s website– Art and Science of Low Carbohydrate Living/Performance http://www.artandscienceoflowcarb.com/ In the August 2015 issue of BJSM you’ll find a series of paper on weight loss and physical activity: http://bjsm.bmj.com/content/49/14.toc Dr Aseem Malhotra’s paper: It’s time to bust the myth of physical inactivity and obesity: you can’t outrun a bad diet (if you want to be thin) http://bjsm.bmj.com/content/49/15/967.full (OPEN ACCESS) Coauthors are Professor Phinney and Professor Timothy Noakes. Professor Stephen Blair’s rebuttal: Physical inactivity and obesity is not a myth: Dr Steven Blair comments on Dr Aseem Malhotra's editorial http://bjsm.bmj.com/content/49/15.toc Professor Kamal Mahtani’s editorial: Physical activity and obesity editorial: is exercise pointless or was it a pointless exercise? http://bjsm.bmj.com/content/49/15/969.extract Two relevant BJSM podcasts include: 1) Professor Tim Noakes interviewed by Professor Peter Brukner http://ow.ly/PQlld 2) Dr Aseem Malhotra discussing the debate around his editorial above http://ow.ly/PQlNL

BJSM editors appreciate that nutrition is a controversial issue (not sure why, but that’s OK) so please note the Prof Phinney’s competing interests are listed in http://bjsm.bmj.com/content/49/15/967.full BJSM revels in debate and publishes quality material. Hence, you can see divergent views represented above and we have commissioned an editorial from respected scientists who feel that protein, or carbohydrate, deserves greater prominence. You submissions are welcome via the BJSM’s various channels – ‘print’, rapid response, blog, Google plus community, twitter, Facebook. Or email karim.khan@ubc.ca