How does diabetes mellitus lead to diabetes ketoacidosis?

Sugar is the source . Sugar is the source of energy in the cells and if you dont have insulin, than glucose can not be used to produce energy.That makes body release a hormone which breaks down fat as an alternate source of energy, in this process there is production of ketones, too much ketones get in the blood and cause ketoacidosis it is more common in type 1 diabetes which is Insulin dependant, and if not enough insuli.