missus - eat protein - fills you up for longer.
I've been testing it. Breakfast of ham, avocado, tomatoes and a boiled egg fills me up for about 4 hours, breakfast of cereal about 30 minutes, breakfast of loads of fruit with yoghurt about 90 minutes.
Same at lunch time - I had a burger with loads of homemade coleslaw yesterday (no bread, but that's a personal intolerance thing for me), sweetcorn, salad etc, piece of dark chocolate... filled me up for 6 hours. Didn't even think about food in between. When I was at school I was trying to eat sandwiches at lunch time, but I'd be starving by 3 having eaten at 12.30.