That was the one statement in the article that jarred me. Benign dietary ketosis (as opposed to diabetic ketoacidosis) is the result of incompletely burning fat for energy (ketones are the actual leftovers). It is not a gimmick, just a physiological process. It is theoretically possible to eat a low-carb diet, use fat for fuel, lose weight and never be in ketosis. Most people's bodies, however, are not highly efficient at metabolizing fat, especially at the beginning of a low-carb WOE; hence, they produce ketones.

Most bodies will accustom themselves to using fats for fuel -- that's why a low-carb diet can work in the long term. A body, once accustomed to using fats for fuel, will eventually find some new weight set point, if one has been losing weight. That's true, however, for any weight/fat loss plan.

Cannabilizing muscle protein for fuel occurs only when there is not enough protein in the diet to meet intense or sustained energy demands (say, from exercise); it's easier for the body to get energy quickly from protein than fats.

Unfortunately, most people will lose *some* muscle (the amount varies) as well as fat on a low-carb diet. Adequate dietary protein minimizes that amount. Resistance training will thicken existing muscles, counteracting the loss from the diet.