Carrot Kid
The child at a party whose parents won't allow them to eat the food being served, providing the child with carrots or other veggies to eat while the other children get cake, ice cream, and other sugar-loaded foods.
"I'm not into sugar for kids...but you don't want your kid to be the carrot kid. There's always the kid at the birthday parties carrying a bag of carrots. You've got to let them eat a little cake." --Tobey Maguire