Yes, they do, but that's more due to the fact that they're only 3 and 4 (and 1!). When they get bigger I am hoping I have taught them enough that they will choose good foods to eat (although we rarely have really junky stuff int he cupboards) like fruit and veg before the package snacks. I am trying to get them to do this now. We go through alot of fruit and veg inour house anyway, and I can forsee that we will oonly be going through more as time goes on! If you think each child might eat 2-3 bits of fruit a day, for us, with 3 children that's 15 peices of fruit a day, plus me who wil go through 3-4 (DH won't eat much fruit!) So all up about 18 bits of fruit a day...woah baby!!!!!!
But I would say if you don't want them eating so much, put a limit on it to two bits of fruit a day. Specially while they are home at the moment on hols!! Once they go back to school, you will probably find you fridge and cupboards won't be raided so badly every day!

