DuncanEarl said:Are you a vet?
No.
As Lisa suggested, I don't think I would bother with the pototo and the carrot. They really don't need vegetables and they probably won't help. You could try a adding a little pumpkin. A tablespoon per couple of cups of food. This is not the case of more is better, as too much will have the opposite desired effect. In a couple of days you could start adding in your pups regular food. You never said what he ate. If it's not on the WDJ list of foods, now would be a good time to get a new food.
Good luck with your boxer. I hope he is on the road to recovery.