I have to disagree with some of what Luscious has posted above.
The brain runs, if anything, better on ketones than carbs (sugars) It's true that a certain amount of sugar can be made from protein in the liver , but the primary fuel for all of the body in a low carb diet is broken down fats, i.e. ketones.
The metabolic advantage has nothing to do with easing the liver, but how the body uses ketones for fuel and the difficulty of storing boidy fat in the abscence of insulin. In several studies done in the last couple of years, it has been shown that low carb dieters can lose more weight while eating more calories than low fat dieters. Numerous people have posted stories of losing weight on a higher low carb dietary calorie intake that what they would gain on in a low fat diet.
Nyah Levi