Flavors can be made with many chemicals, none of which are required to be disclosed on the product label, so it can be very hard to determine what harmful ingredients lie within them, especially for people with food allergies. Flavors derived from a specific ingredient likely only use chemicals available in that food, so are slightly more regulated. In general, flavors are created to make food more palatable, so they can be addictive, leading consumers to eat more without feeling full.