The Science of Ketogenic Exercise

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Introduction/Summary. There is remarkably little scientific research available around exercise while on a ketogenic diet. This section is a brief review of the available studies.

• Phinney-1983. This study looked at the effect of four weeks on a Ketogenic Diet on 5 elite cyclists, and found that their endurance was maintained.
  • The diet was 15% of calories from protein, 85% from fat, with less than 20g of carbohydrate.
  • Subjects were performed VO2max and endurance tests before and after the Ketogenic Diet.
  • Unlike typical fat metabolism, the oxygen cost of calories was not different on the Ketogenic Diet.
    • There are some similar observations from other non-exercise studies.
  • The RQ on the VO2max test dropped from 1.04 to 0.9, and on the endurance test from 0.83 to 0.72, indicating a shift in substrate metabolism.
  • The endurance test did not include any fuel, just water. It is likely that the endurance test would have had a better result in the control condition with carbohydrate supplementation.
  • Blood glucose during the endurance test was similar after the Ketogenic Diet to before, but the rise and fall were somewhat reduced. At no point did blood glucose drop to the point of hypoglycemia. Blood glucose provided an estimated 28% of calories on the normal diet and 9% of calories on the Ketogenic Diet.
  • Blood levels of 3-hydroxybutyrate, which indicates ketogenisis, were insignificant on the normal diet and elevated on the Ketogenic Diet.
  • Muscle glycogen levels where higher before the endurance test on the normal diet than on the Ketogenic Diet (143 and 53 respectively). Both tests had similar muscle glycogen levels after the endurance tests. It is interesting to see that muscle glycogen levels were replenished somewhat on the Ketogenic Diet, even though the subjects continued normal training for the four weeks.
  • The five subjects had an endurance time of 147 minutes on the normal diet and 151 minutes on the Ketogenic Diet. However, the individual responses are rather different.
    • Two subjects dramatically increased their endurance time on the Ketogenic Diet, one by 57% and another by 30%. The subject whose endurance improved by 57% had much lower final muscle glycogen levels on the Ketogenic Diet than the normal diet (41.5 compared with 59.2).
    • One subject had an almost identical endurance time.
    • Two subjects had a dramatic decrease in their endurance, one by 36% and another by 28%. The subject that decreased their performance by 36% had complained of overtraining and had reduced his training level the month before the trial.
      • The subject that reduced their performance by 28% has higher final glycogen levels after the ketogenic endurance test than the normal diet (38.1 compared with 58.4).

See Also

• The classifications and types of Low Carbohydrate Diet.
• An introduction to the Ketogenic Diet.
• My experiences with ultrarunning on the Ketogenic Diet
  • How the Ketogenic Diet can be used for the treatment and management of disease.
    • Using the Ketogenic Diets to mitigate and treat Epilepsy
    • How Ketogenic Diets might help with Cancer
    • A look at the possible mechanisms of action of the Ketogenic Diet
  • Health Risks of the Ketogenic Diet
    • Health Checks for the Ketogenic Diet
    • Supplements for the Ketogenic Diet
  • The time frame and changes that occur with Ketoadaptation
  • What are Ketones
    • How to measure Ketones
    • What ketone levels to aim for
  • The pros and cons of the Ketogenic Diet for athletes
    • The Science of Ketogenic Exercise
  • The Types of Ketogenic Diet
    • The "traditional" Ketogenic Diet based on the Ketogenic Ratio
      • The ways the Ketogenic Ratio can be calculated
        • The different definitions of Net Carbohydrates
    • Low Glycemic Index Treatment
    • MCT Diet
      • MCT
    • Modified Atkins Diet (M.A.D.)
• My Ketogenic Recipes
• Non-Ketogenic Low Carbohydrate Diets