Become an expert. Always investigate anything your doctor tells you. If your doctor says you have heart disease, get at least 5 books on heart disease and study them. Keep it simple and basic. The low-fat fad will pass, because such diets do not work.
Free information is on our leanbody page.
This is where many people cut too many corners. Take the stairs instead of the elevator. Go for walks after supper. Stay away from that television. The Mindconnection fitness store has free exercise information, plus excellent equipment to help you get in shape and stay in shape.