You need to approach this as an exercise in habit building. Build up a healthy approach to food in steps, not all at once. Saying 'I'm going to eat healthy from

You need to approach this as an exercise in habit building. Build up a healthy approach to food in steps, not all at once. Saying 'I'm going to eat healthy from today' is unlikely to work. Saying 'in 6 months I will have developed healthy eating habits' is a much better approach. Then build this habit step by step. First: reduce sugar. Build up a strong habit of refusing sweet things, one type at a time. Refuse donuts - or whatever, but pick one thing that will be hard but not impossible for you to resist. Once that's a habit and you no longer crave donuts, add soda to the list. Then add cake. In this time, you have to be very firm with these habits. In six months once the habits are strong, you can break them sometimes.