The obvious answer is that there is no glycogen left, but I recall that it proceeds more slowly with time during a fast. A table in the notes shows consumption declining over time. I recall that there is some kind of control that governs this slowing of glycogen degradation, but I can't remember the name of the process, feedback, or enzyme that is responsible. I have tried Marks' Basic Medical Biochemistry, Silverthorn Human Physiology , the class notes, and Google. They were all a no go. the way the question is worded I am looking for something that acts on phosphatase 1 and phosphorylase.