Answer: To compensate for low concentrations of carbohydrates, the body hydrolyzes TAGs to free fatty acids and glycerol, the latter of which is provided in ample supply to feed the -citric acid cycle.
When the body is under starvation condition, low concentration of carbohydrates occurs, then the body hydrolyzes triacylglycerols to fatty acids and ketone bodies. Moreover, the acetyl CoA cannot be transformed into pyruvate so fatty acids cannot be converted into glucose. The other potential source of glucose is amino acids but this process is inherently inefficient and weakens the body so protein must be preserve.
