I wouldn't worry too much...I've been coming (Spain)here for about 10 years and it won't make a blind bit of difference apparently they have obesity problems? however kids are fatter at home (UK) the food here is generally pretty good(it's definately tasty)kids seem to spend far more time out playing games, football, cycing etc and there's certainly very little veggie facist activity going on(if there is it's by middleclass Britsh travelling grungies in their ragtag caravan/motorhome that mummy and daddy paid for), the kids know where food comes from and don't seem too bothered either...how often would you see kids at home eating all types of seafood, rabbit, baby goat etc etc?
Steve...currently lounging for a month, enjoying watching the TDF on and off whilst dipping in the pool at a mates Villa in Sothern Spain.