What is the effect of fasting on glucose?

There are 4 levels of fasting: Fed (within 4 hours of eating, used glucose is exogenous) Fasted (4-12 hours after eating, liver stimulate glycogenolysis) Early starved (12 hours - 16 days, gluconeogenesis starts) Late starved (after 16 days, only gluconeogenesis and glycogenolysis done)