I think it will be pretty hard, and probably inaccurate, for anyone else to try to help out on the food thing, since all kids (and adults) vary so much. I found the biggest help was to start keeping a spread sheet of what we carried and what we ate, meal by meal. This is important, since often we all eat less on the first night out, and then start to eat more than aat home on day two or three. I also hate to prepare food and then not be able eat it. What do you do with it then.
It's also worth trying to work out at home how much you need. Is 1 cup of rice enough to feed you, or do you need 1 & 1/2. This will all help to level it out.
Good luck, Rod