you can put on lean muscle/cut on just about anything. You get fat when you gorge and don't control your input/output.

While I completely disagree that your body fat is too high (bodybuilders seem to think they are the only ones that can use steroids... I'd also advise you just diet without the deca. (I've never seen a "just deca" cut cycle, though I've seen them with test. Still I'd just diet without it, because that's obviously the problem.)