Metabolic therapy using ketogenic diets is a promising approach for brain cancer management that targets the common metabolic malady of most cancers, the aerobic fermentation of glucose. The KD lowers blood glucose and elevates blood ketones to target tumor energy metabolism. Although plasma levels of glucose and ketone bodies have been used separately to predict therapeutic success, daily glucose fluctuations can make it challenging to link changes in blood glucose and ketones to the efficacy of metabolic therapy.