When I was a kid one of my friends moms told us kids that you could die if you ate too many Nanaimo bars (coconut/chocolate/crumb base with custard creme middle and hard chocolate top layer), while we were all oogling a plate of them. Obviously, she told us this because then we wouldn't eat them all, but it stayed in the back of my head for years and years afterwards.
A childhood belief about dangerous food

others believed things like this
- My mum told me that cold custard (which I hated) was in fact Banana Blancmange. I lapped it up for years.— Chalky
- Chocolate, they say, rots your teeth. I believed if you drank chocolate milk, your bones would be brown.— Dellio
- I used to belive chocolate milk came from brown or chocolate cows.Anon
- I used to believe that chocolate milk came from chocolate cows.— Scott
- When I was little my mother told me that the chocolate sprinkles you put on ice-cream were ants.Anon
- my dad told me that hershey park was made completely out of chocolateAnon