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Muscle Glycogen Storage On A Ketogenic Diet
Research by Volek and Phinney found muscle glycogen storage on a Ketogenic Diet is the same as on a high carbohydrate diet, once the individual is Keto Adapted.
The Premise of Metabolic Inflexibility
1) High Carbohydrate Diets make you "Glucose Dependent". The body utilizing glucose well but is inefficient at burning ketones/body fat.
2) Ketogenic Diets make you "Ketone Dependent". The body utilizing ketones but is inefficient at burning glucose.
This seem logical. It would appear that both diet make you Metabolically Inflexible.
However, research indicates that it may not be the case.
A Low-Carbohydrate Ketogenic Diet Combined with 6-Weeks of Crossfit Training Improves Body Composition and Performance | ClinMed International Library | International Journal of Sports and Exercise Medicine
Despite the significant reduction in carbohydrate intake and slight decrease in caloric intake, the LCKD group was able to adhere to CrossFit training at least 4 times per week with no adverse side effects reported. Additionally, there were no significant differences in performance or power outcomes between the LCKD (Low Carbohydrate Ketogenic Diet) and CON group after 6 weeks of CrossFit training.
High Rates of Fat Oxidation Induced by a Low-Carbohydrate, High-Fat Diet, Do Not Impair 5-km Running Performance in Competitive Recreational Athletes
It is argued that athletes eating a LCHF Low Carbohydrate High Fat) diet develop impaired “metabolic flexibility” (Burke, 2015). This experiment shows the opposite. On the HCLF (High Carbhydrate Low Fat) diet subjects showed an almost complete dependence on carbohydrate oxidation during exercise at >80%VO2max. In contrast when eating the LCHF (Low Carbohydrate High Fat) diet, athletes retained the capacity to oxidize both fat and carbohydrate at high rates during exercise at that intensity whilst maintaining their performance capacity. Superior metabolic flexibility would likely be beneficial during ultradistance events as maximal fat oxidation rate measured during a graded exercise test is a significant predictor of performance time during the Ironman Triathlon (Frandsen et al., 2017).
These studies show that a substantial contribution of fat oxidation to energy use even at very high exercise intensities, may have been overlooked in the past.
SNR #82: Dr. Jacob Wilson – Ketogenic Diets, Strength & Body Composition
For some reason, this interview is no longer on line. However, below are some of notes...
Interval Sprint Training
18:40 seconds minute mark
a) Sprint 1: 40% Glycogen.
b) Sprint 6: 9% Glucose, 40% fat.
Multiple Interval Sprints produce the shift to fat oxidation.
The Take Home Message
1) The most important aspect of this information is that Keto Adapted individual appear to be Metabolically Flexible.
2) Keto Adapted individual utilize ketones/body fat as the primary source of energy; preserving and only using glucose on a "As needs basis".
Based on this information, on "days you want to go days you want to go fast by tapping into your maximal intensities, your goal climb or race," it appears you have more than enough muscle glycogen for what you need.
You don't need to consume a high carbohydrate diet.