Diabetic ketoacidosis develops when you don't have enough insulin in your body. When this happens, sugar (glucose) can't enter your cells for energy. Your blood sugar level increases, and your body begins to break down fat for energy. This process produces toxic acids known as ketones. Excess ketones accumulate in the blood and eventually "spill over" into the urine. It it’s left untreated, diabetic ketoacidosis can lead to a diabetic coma and caused fatal death.