Under conditions of fasting or starvation, no carbohydrate intake occurs,so the body is forced to use lipids and protein as fuels. A problem will arise with the body’s oxaloacetate levels if no carbohydrate is coming in. An adequate pool of oxaloacetate is important for continued TCA cycle function, but the oxaloacetate pool may be depleted by other metabolic processes under starvation (recall the anaplerotic role of the TCA cycle)