For most people portion control is a big issue. You've said you feel you already have a health diet, rather than trying to change what you are eating, just cut down. Not drastically, but try to not go back for seconds (or thirds ) or if that's psychologically too hard, make each portion smaller. Eat until you are satisfied, but not full. Be sure to have a glass of water with your meal or better yet before you eat. Its harder than it sounds, but if you can do it you will likely lose weight.