But if we're under certain conditions, for example, starvation conditions, the brain will actually use ketone bodies. In fact, 75% of the energy needs of the brain will come from the breaking down of ketone bodies. So we see that normally, acetoacetate and D three hydroxybutyrate are fuel molecules that are normally used by the heart and the renal cortex over glucose. In fact, under certain conditions, when we're starving, the brain will also use ketone bodies. In fact, 75% of the energy needs of the brain will come from the breaking down of ketone bodies. So let's suppose our liver cell produces these ketone bodies.