Ketosis is the accumulation of ketone bodies or ketones in the blood. Ketosis occurs in healthy people during fasting and strenuous exercise. In excess, blood ketones can produce a toxic level of acid in the blood, referred to as ketoacidosis. Ketoacidosis is a known and life-threatening complication of type 1 diabetes and has been described in some cases of healthy people eating a very low-carbohydrate diet. Further, the "keto diet" has gained attention as a potential weight loss tool.