Exercise. Exerciseexercisexercise.
Also, cook all your food from scratch. If that means making your own cheesecake 100% from scratch vs. buying a cheesecake from the store, always make your own cheesecake. Is it the healthiest option? No. But it will always be better than most of the pre-made stuff you get at a store.
I lost 1/3 of my body weight by adding exercise, sticking with it, and upping the challenges as the weeks/months went by. I minimized eating out. I eat TONS of carbs, as I rarely eat meat and don't consume much dairy, besides half & half in my morning coffee. But I stand by the long-term power of exercise.
I'm now a very fit, strong, athletic size 4