The acid-base balance can also be affected by metabolic processes, for example ingestion, metabolism or excretion of substances with acidic or alkalotic properties. For example, a patient in type I diabetes who forgets to take their insulin will switch to burning fatty acids because they cannot metabolise carbohydrates. Burning fatty acids produces ketones which are acidic; this is diabetic ketoacidosis. These acid-base imbalances are known as metabolic disorders.