DiPasquale re-engineered the original Anabolic Diet and is now calling it the Metabolic Diet. I borrowed the original from my PL friend, but the original is no longer published. However, he basically uses the same format, same diet in his new "Metabolic" diet; he just seems to plug his supplements more in the new format. That was really the only difference I could find.
You always lose some amount of muscle when cutting - I think that's inevitable, whether your natural or not. But if my measurements are any indicator, I'm not losing very much muscle. For example, my arm measurement, before I started cutting, was 12 3/4 inches flexed. About 6 weeks into my last diet, I was down to 12 inches flexed, but I also lost fat off my triceps. 4 weeks into my second round of dieting - and 12 weeks total dieting, between the two comps - I'm still at 12 inches flexed. I have a ltitle stubborn fat left on my tris, so that measurement may decrease a little more before I'm done, but since I'm also getting stronger, I'm not that concerned right now. If my chest/arm measurements start to drop significantly, then I'll start worrying.
My body seems to like this type of diet, because I don't flatten out that much, even after 5 days of low carb. But other people feel like they really flatten out, which makes them think they're losing muscle. Like Spatt's said, that's gotta be water loss. IMO, you'd have to be starving yourself to lose significant amounts of muscle, especially if you're training heavy.