@conficker, @giftessiet. The body does not degrade “muscle” or “muscle proteins (e.g actin & myosin)” in peroids of starvation. They degrade glycogen rapidly and as starvation is prolonged, the glycogen stores get depleted and the body has to utilize fats as an alternative. Proteins are rarely being used unless in very extreme cases. Ketogenesis is necessary cause it makes available ketone bodies which can be utilized by the brain and others
extra-hepatic tissues. The liver cannot even utilize these ketone bodies despite being the main producer of these bodies and this is because the liver cannot undergo ketolysis which is necessary for the utilization of ketone bodies.