There are two fuels your body burns for energy. Glucose, the primary fuel, comes from eating carbohydrates. When your body runs out of glucose, it turns to its secondary fuel source: your own body fat. When you reduce your intake of carbohydrates, your body must convert fat into energy, and this metabolic state is called "ketosis." So being in ketosis simply means living off your fat stores. Assuming you're overweight, this process is not only safe-it's desirable!
One reason why people become overweight in the first place is that their bodies have great difficulty in using this backup fuel system. Almost 50 years ago, scientists demonstrated that obese and overweight people differed dramatically from people of normal weight in that they were very resistant to developing ketosis. The Atkins program helps your body activate its fat-burning system by restricting its primary source of fuel-glucose.

Ketosis is absolutely safe-unless you happen to have no excess body fat. So, why do so many people think ketosis is dangerous? Perhaps because the term is often confused with another K-word. Ketoacidosis is a potentially dangerous condition that occurs in a diabetic whose blood sugar levels are out of control. Ketoacidosis is not experienced on the Atkins plan. We have diabetic patients at The Atkins Center in ketosis whose blood sugar is under control, and they are burning fat and losing weight.

Anyone who is diabetic and wishes to follow the Atkins weight-loss program (or any diet) should seek a physician's supervision.

Selected reference: Bloom, W., "Fasting Ketosis in Obese Men and Women." J. Lab. & Clin. Med. 606, 1962; 784.
FAQ: Atkins