Milk isn’t milk without a cookie. But have you ever wondered why you think that? Drink-pairing preferences form at an early age, a new study suggests, which is why it’s important to start pushing healthy choices–such as water–early on. Kids learn to associate colas (Diet Coke!) with salty and calorie-rich foods (French Fries!), but amazingly, they eat more veggies when they’re paired with water instead.