"ketones" are fractured fat cells. they can not be used for anything other than fuel and are only worth 7 calories instead of the 9 usually found per gram of fat. ketones are made in the absence of carbohydrates and or food. the body will initially try to preserve muscle when starvation sets in. it does so by fractureing fat cells (either stored or dietary ) into ketones wich then become an effeicient source of energy. so instead of wasteing muscle the body protects it via a hormonal responce to the emergency of starvation, luckily for BBers, we can cause the same thing be avoiding carbs in our diets. once blood sugar dips below 70, most people reach a state commonly reffered to ketosis.
there is no proof as to how long the body can stay in its protective state so some keto diets try to reset the hormones via recarb/reffeding the body. these style "cyclic keto diets" offer the greatest benifits to the bbing lifestyle. its also very hard to follow at first. so alot of people give up. if your not a well disaplined individual you may want to ease into the diet useing something like Atkins diet. after that u might try lyle mcdonalds ultimate diet 2.0