I believe there are three kinds of weight loss. The first comes from taking in more energy than you expend or excrete. We know now that this is not a simple caloric calculus, but I won't get into that in this post. The second is water weight, which is most of the weight you tend to lose when you are eating an equi-caloric Paleo versus standard diet.. And the third is reducing carbohydrates. I believe, other than surgery or accident, that that's the entire universe of possibilities.
Jim Swayze