You have to completely change your diet and stick to it. There are many good diets out there like the Mediterian Diet, the Keyto Diet, Low carb diet, Vegitarian, Atkins diet, and so on. The idea is to not eat or drink foods high in calories for the most part. Its hard to count calories for a extended period of time, but much easier to just stick to a diet. Foods/drinks where people mess up= deserts, candy, soda, cakes, breads, junk food, starches/high carbs, ice creme, pizza, fried foods, lots of salad dressing, etc....stick to real food like fish, salads, veggies, chicken, drink water only, if coffee...drink black, etc etc then you have to stick with it for life.....and also stay active, not always working out, but at least walking a mile or two each day.....just don't sit around.