I think it depends on estrogen levels. We all know that estrogen helps in the anabolic side of certain steroid cycles. But we also know that estrogen facilitates fat deposition. So if you are on a cycle with high estrogen levels, you may put on some fat. I am not sure if that fat is intra-muscluar, sub-cutaneous, or even visceral. But that may be the explaination. Another explaination to your confusion may be that people's body composition may change after they are on steroids, but the amount of fat mass may actually increase (since it is a percentage). However, elevated testosterone levels lead to fat loss. But I think this is when estrogen is minimized. So, my answer to you is estrogen. More estrogen leads to bigger gains, but you may aslo be putting on some fat. Minimize estrogen and you will put on some lean weight and lose some fat. Someone correct me if I am wrong.