The most effective
diet is one that incorporates plenty of lean
protein (chicken, fish, lean beef, beans, etc), low/no fat dairy, 5-7 servings of vegetable daily, 1-2 servings of fruit, whole grains, plenty of water and no junk food, which includes anything made with processed (table sugar) and white flour, white rice, etc. Has to be lifestyle changes; not just a "diet".
You have to also incorporate a moderate exercise program.