First, a simple explanation of the process: the carbohydrates you eat are converted to glucose, which is the body’s primary source of energy. Whenever your intake of carbohydrates is limited to a certain range, for a long enough period of time, you reach a point where your body draws on its alternate energy system, fat stores, for fuel. This means the body burns fat and turns it into a source of fuel called ketones. (Ketones are produced whenever body fat is burned.)
When you burn a larger amount of fat than is immediately needed for energy, the excess ketones are discarded in the urine. Being in ketosis means your body has burned a large amount of fat in response to the fact that it didn’t have sufficient glucose available for energy needs.
Dietary ketosis is among the most misunderstood concepts in nutrition because it is often confused with ketoacidosis, which is a life-threatening condition most often associated with uncontrolled insulin-deficient Type 1 diabetes. In the Type 1 diabetic, the absence of insulin leads to a toxic build-up of blood glucose and an extreme break-down of fat and muscle tissue. This condition doesn’t occur in individuals who have even a small amount of insulin, whether from natural production or artificially administered.
Dietary ketosis, however, is a natural adjustment to the body’s reduced intake of carbohydrates as the body shifts its primary source of energy from carbohydrates to stored fat. The presence of insulin keeps ketone production in check so that a mild, beneficial ketosis is achieved. Blood glucose levels are stabilized within a normal range and there is no break-down of healthy muscle tissue.
The most sensitive tests of ketosis (“NMR” and “blood ketone level”) show that everyone is in some degree of ketosis every day, particularly after not eating overnight and after exercising. Ketosis is the body’s survival system. It is not an abnormality nor does it present any medical danger, except to a Type I insulin-dependent diabetic. The body functions naturally and effectively while in a state of dietary ketosis.
The Lean for Life Program is mildly ketotic and then, for only a very brief portion of the program. Some of the benefits many people experience while in a state of dietary ketosis for intentional weight loss may include rapid weight loss, decreased hunger and cravings, improved mood, increased energy and, as long as protein intake is adequate, protection of lean mass.
On a different note: Recently, a great deal of attention has been paid to the benefits of ketosis to medical conditions other than obesity. For example, The Boston Globe ran a story on January 15, 1996 describing how ketosis has become an important therapy for childhood epilepsy. “No one is sure why it works, but the high fat/low protein/low carbohydrate diet seems to push the body into a starvation-like state called ketosis,” says Dr. Gregory Holmes, director of the epilepsy program at Children’s Hospital in Boston. “Patients are first “starved” for several days to deplete the body’s stored sugar, then put on the diet, which contains almost no carbohydrates. Soon, because the body has no glucose for fuel, cells begin burning fat from the diet instead, which slows the frantic firing of brain cells.” “Burning fats in the absence of glucose leads to the production of fatty molecules called ketone bodies. Most children stay on the diet for two years, he says. When it works right, seizures rarely return, even after normal diet is resumed. So far, there is no evidence that the diet raises the risk of atherosclerosis, heart disease or stroke.”
Linda Nebeling and Edith Lerner wrote of how ketogenic diets are also of proven benefit in certain childhood cancers in the Journal of the American Dietetic Association in June, 1995. “Certain tumors, particularly those that are poorly differentiated and slow growing and have a limited blood supply, are known to use glucose as the primary source of fuel. Shifting the prime substrate for energy metabolism in the host from glucose to ketone bodies by means of a ketogenic diet, thereby decreasing the availability of glucose to the tumor, could potentially inhibit tumor growth.” “Urinary ketone levels can be monitored by the patient at home to track the level of ketosis and, thus, dietary compliance.” “The diet is not flexible. Every gram of carbohydrate has to be counted because carbohydrate intake above 10% of total energy intake will knock the child out of ketosis. Among the patients I worked with in this study, their cancer was considered to be in remission, but their prognosis was not good. Because the ketogenic diet offered these children and their families a treatment option that was less invasive than their previous treatments, they found it appealing.”