built simultaneously, even during calorie-deficit periods. I've done it myself, and I have the BYU BodPod (and chest/thigh/bicep/calf tape measurements) to prove it. From January 24, 2008 to April 29, 2008, I reduced my bodyfat from 26.0% to 17.2%, my bodyweight from 258.4 to 233.6, and *increased* my lean muscle mass by 8.8%. I tracked my progress via BodPod measurements every two weeks, and the numbers were steady and consistent. No doubt about it. I got stronger, lighter, and leaner, but I had to carefully monitor my protein intake to accomplish it.