Ketones are acidic waste products produced when the body burns fat for energy. A buildup of ketones in the blood is very dangerous, and can lead to ketoacidosis and diabetic coma. In case of type 2 diabetes, body may not get sifficient glucose to use as energy, and in type 1 diabetes, it gets none. In such a situation, the body uses fat to produce energy and use or "burning" of such fat at a unusual faster rate may cause presence of ketones in the blood stream. Joslin Diabetes Center describes emergence of ketones in the human body in these words: "Ketones are produced when the body burns fat for energy or fuel. They are also produced when you lose weight or there is not enough insulin to help your body use sugar for energy. Without enough insulin, glucose builds up in the blood. Since the body is unable to use glucose for energy, it breaks down fat instead. When this occurs, ketones form in the blood and spill into the urine."