Diabetic ketoacidosis is a complication of diabetes. It occurs mostly in people with type 1 diabetes. Diabetic ketoacidosis occurs when a lack of insulin prevents glucose in the bloodstream from entering the cells. Without adequate glucose, the cells burn fat for energy, producing compounds called ketones. Ketones supply some energy, but they also make the blood too acidic. There are several causes of ketoacidosis. Which of the following is a cause of ketoacidosis?