doing a fat fast, or eating a low-protein keto diet. The body doesn’t have enough carbs or protein coming in, so it doesn’t have enough oxaloacetate to burn fat in the Krebs cycle. Plus, some of the oxaloacetate is redirected to fuel more gluconeogenesis (GNG) to make glucose for the cells that have no mitochondria and can only run on glucose, like the brain neurons and red blood cells. This is why you lose muscle and lean mass when fasting for long periods.
