We need to consider food as a fuel. And nothing else. It gives us energy. And construction components. And affects good or bad on our engine lifetime. Like fuel for car.
We need to forget such term as an appetite. It is nothing more than a drug effect, pleasure seeking. We have a lot of, hundreds and thousands other things in our life making pleasure for us. Food is just one of them.
Food should become only necessity in terms of health, energy and construction materials. If we exclude appetite then we can avoid harmful food, fat. We can become more thin, healthy, beautiful and ... happy despite on that we have no appetite pleasure.
Stop taking pleasure from lunch. Take pleasure from sport, love, arts, nature...