Ketogenic Diets For Gymnasts? What Does This Mean?

Posted: December 4, 2013 in Uncategorized
Tags: , , , , , ,

I came across this study in the International Society of Sports Nutrition Journal, http://www.jissn.com/content/9/1/34/abstract.  This study took 8 elite gymnasts between 20 and 26 years old and placed them on a ketogenic diet.  They measured body fat and the following performance tests; hanging straight leg raise, ground push-up, parallel bar dips, pull-up, squat jump, countermovement jump, and 30 second continuous jumps.  Diet consisted of green vegetables, olive oil, fish, and meat, and virtually no carbohydrates.  after 30 days significant losses were seen in body composition and weight with no difference in performance.  The authors concluded this may be beneficial to decreasing weight and fat mass without decreasing performance, but is this true?

First, let us look at the study group.  The researchers took 8 elite gymnasts under 30 years old.  Does this accurately represent the vast majority of the population? The answer to that is most definitely no.  Also, let us look at this group and the exercises picked for the study.  Those are exercises that elite gymnasts have probably been doing since they were 5 or 6 years old.  The fact that they did not do better or worse on the tests does not surprise me.  They have adapted to those stimuli.  Think of the exercises you have done on a continual basis for a prolonged period of time, don’t they become easier?  Try for a period of around 20 years or so.

Also, the exercises they chose do are not energetically taxing, especially when an individual is adapted to doing them.  Many studies have described the opposite of this one in terms of carbohydrate intake and anaerobic work performance.  This study took 8 healthy subjects and put them on a bike test.  They did this 3 days with 50% carbs and 3 days with 5% carbs.  The conclusion was “LCD is detrimental to anaerobic work capacity…” (http://www.ncbi.nlm.nih.gov/pubmed/9272770).  This is most likely due to the decrease in muscle glycogen.

The gymnasts did lose body fat and weight.  Is this a good thing?  I picture gymnasts as already pretty lean.  I would have liked to see some cortisol numbers because my guess is they were probably a little stressed.  Another study looked at wrestlers, performance, weight loss, and low carb.  With the weight loss associated with low carb there was decreased mood and increased fatigue,http://www.setantacollege.com/wp-content/uploads/Journal_db/Weight%20loss,%20dietary%20carbohydrate.pdf.  The gymnastics study did not record the mood of the athletes.

When we see these studies we cannot jump to conclusions.  After reading this study I will still be consuming my post workout carbohydrates for performance.  Do any of you have thoughts on this?  

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