I've been on the metabolic diet for about a month now, and have been doing very well. I was trying to keep my total daily caloric intake at maintenance level, but ended up losing more weight than I wanted (from 197 to 189), so I'm actually about 500 calories over maintenance and am creeping back into the low 190's. I have definitely retained all of my muscle mass, and probably gained a bit, and have lost a few pounds of fat. I have never eaten very high carb, so the transition was rather easy for me. All week, energy is good, lifts have been going nicely, no real problems to report. I do peform a full 2 day refeed on the weekends, aiming for about 700 grams carbs on friday's and 400 grams on saturdays. I don't do it becasue I feel I need carbs, I do it for the supposed "anabolic effects" to enhance my early week workouts. I plan on staying on the diet for at least 6 months, and depending on where I'm at, possibly longer.