Glycogen branching enzyme leads to increased osmotic pressure resulting in cellular swelling and death. The tissues most affected by this disease are the liver, heart, and neuromuscular system, areas with the greatest levels of glycogen accumulation. Abnormal glycogen buildup in the liver interferes with liver functioning and can result in an enlarged liver and liver disease. In muscles, the inability of cells to efficiently breakdown glycogen due to the severe reduction or absence of branching can lead to muscle weakness and atrophy. At least three mutations in the GBE1 gene have been found to cause another disease called adult polyglucosan body disease (APBD).
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"