What does it mean when a diabetic has ketones in his urine?

The presence of ketones in a diabetic's urine indicates that the body is converting energy from fat instead of glucose due to an insulin shortage, according to the American Diabetes Association. Trace ketones amounts warn of their accumulation while moderate to large amounts mean the diabetes is out of control.

When ketone levels are high, a diabetic may have a dry mouth and feel nauseous, tired and confused, states the American Diabetes Association. If left unchecked, high ketone levels may upset the blood's chemical balance and have a poisonous effect on the body. Diabetics, especially those who suffer from Type 1 diabetes, should check their ketone levels regularly with a simple ketone urine test.