For those substituting this for a lifestyle, I agree. But somebody who weighs 600lbs, they need more help then diet.
The first thing they need is love. Self love. When you decide you are worth loving, you learn that not stuffing every kind of food in your mouth is a truer way of loving yourself. You don’t have to deprive yourself of sweet/salty/whatever foods, but you love yourself more and better by not eating them so frequently. You can change the way you look at food, and that helps you change your habits with diet and exercise.