Ketone bodies include fat metabolites such as acetoacetate, beta hydroxybutyrate, and acetone. When the body produces more ketone bodies than the kidneys can filter, the ketone bodies are excreted in the urine, resulting in a positive urine ketone body. If the urine test is weakly positive for ketone bodies, it is a transient physiological change, mainly related to the recent diet, such as people who have not eaten for a long time, eat less carbohydrate food and eat too much fatty food.