Doing a few things right can make all the difference in losing fat instead of muscle. -When you try to lose fat, make sure your start in a SMALL caloric deficit. Going too deep too early will be unsustainable and result in muscle loss since the muscles aren't being fed enough. there's no reason to overdo cardio. You can incorporate it to further your deficit, but don't force it.-You also need to train heavy. Don't only train lightweight for high reps! training heavy helps maintain muscle mass. Source by patrick_enriquez