A 19-year-old female with type 1 DM was admitted to the hosp…

A 19-year-old female with type 1 DM was admitted to the hospital with the following lab values: serum glucose 500 milligrams per deciliter (high), urine glucose and ketones 4+ (high), and arterial blood pH 7.20 (low). Her parents state that she has been sick with the “flu” for a week. Which of the following statements best explains her acidotic state?