Most of my planning and effort goes into dinner (much of which cooked ahead of time). I can resist any distraction as long as I know I've got steak salad and taters waiting for me, with fruit and a little cheese or chocolate for dessert. On rest days I only eat dinner. On active days I'll add a salad or sushi around 2pm. I'm not prescribing this schedule exactly but a lot of our appetite is Pavlovian (clock strikes 12, people around us are eating, etc.)--the urgency of food is in our heads. If you need something to chew on maybe start with pickle spears, carrots, gum, etc.
I wouldn't scrutinize quantities at first--just work on scrubbing out the "big three" (seed oil, sugar, wheat) and rotate in enough nourishing foods to fix any underlying deficiencies. Start with the easy ones like boiled eggs and canned fish then graduate to more dark greens, bone soup, liver, etc.