I believe that since you're brain creates habits and connections between times, places, and events, it's important you take advantage of your habits. Do you find yourself smoking at particular times of day to be hungry? Do you always smoke at the same times? Perhaps your best bet is to pick out specific times in your schedule and make yourself eat (small portions at first) at those times. Be sure to remove smoking from eating times, and build those connections of 12:00 = hungry (or whenever you choose to eat).