Diabetics, and even some health professionals, often confuse two quite distinct metabolic processes - ketosis and ketoacidosis. Ketosis is a perfectly natural and healthy state during which the body uses stored or dietary fat for fuel. In order to enter this state, carbohydrate intake needs to fall below a certain level. Ideally, a healthy metabolism should regularly use ketosis, while fasting overnight for example, to fuel the body's processes and utilise stored fat reserves. Most of the body's organs, the heart for example, in fact run very efficiently on ketones.
Ketoacidosis is quite different and is typically the result of a chronic lack of insulin, not a lack of carbohydrate. With insufficient insulin, the body attempts to fuel itself by breaking down fat and protein stores in an uncontrolled way, a process which results in the blood becoming dangerously acidic. In short, ketosis usually occurs when blood sugars are at the lower end of the normal range, and ketoacidosis occurs when blood sugars are dangerously elevated. Ketosis is a result of low carbohydrate intake, ketoacidosis is a result of inadequate insulin levels.