as the mother of a child w/ life-threatening anaphylaxis allergy to them, i am going to have to say peanuts. unfortunately, they are rapidly becoming a major contender for top cause of death of children in schools. dogs, cigarettes and swiss army knives are all things that are strictly banned form most schools these days and i highly doubt any of those things have ever killed as many children in schools as peanuts now have. nobody can predict when a moderate allergy might turn into one w/ a life-threatening reaction. nobody can predict when a child w/ no food allergy history might suddenly have an anaphylactic reaction to peanuts. i just don't think they are worth the risk to even allow in schools anymore.
as a mom of 5 children that i don't want to be obese or have diabetes, i have to say next on my list is sodas and sweet drinks. my oldest boys are in 6th grade and their middle school has a slurpee machine in the cafeteria. i have promised each boy a $20 bill if they go the entire school year without ever giving in to the temptation and trying one. they've never had soda, never had a slurpee, never had commercially prepared, sugar laden fruit juices. i think a place of education is the last place that should be promoting diabesity.