Glycogen storage disease type I similar, but Ib incurs a few additional problems (described below). Glycogen in liver and (to a lesser degree) kidneys serves as a form of stored, rapidly accessible glucose, so that the blood glucose level can be maintained between meals. For about 3 hours after a carbohydrate-containing meal, high insulin levels direct liver cells to take glucose from the blood, to convert it to glucose-6-phosphate (G6P) with the enzyme glucokinase, and to add the G6P molecules to the ends of chains of glycogen (glycogen synthesis). Excess G6P is also shunted into production of triglycerides and exported for storage in adipose tissue
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"