Glycogen phosphorylase V, McArdle's Disease). More than 65 mutations in the PYGM gene that lead to McArdle disease have been identified to date. Symptoms of McArdle disease include muscle weakness, myalgia, and lack of endurance, all stemming from low glucose levels in muscle tissue. Mutations in the liver isoform of glycogen phosphorylase (PYGL) are associated with Hers' Disease (glycogen storage disease type VI). Hers' disease is often associated with mild symptoms normally limited to hypoglycemia, and is sometimes difficult to diagnose due to residual enzyme activity. The brain isoform of glycogen phosphorylase (PYGB) has been proposed as a biomarker for gastric cancer.
Cyclic ketogenic diet goals of a refeed are threefold: The refueled glycogen stores can then be used for higher-intensity training to maintain or increase endurance / muscle mass after the refeed. Normally this sort of training would be relatively impossible on a pure ketogenic diet, as glycogen stores in the body are almost constantly depleted. The refeed process can lead to gaining fat if more carbs are consumed than needed to replenish glycogen stores. The timing, duration, and macronutrient composition of a refeed are crucial to the overall success of the diet. According to a published article in the "British Journal of Nutriton"