Babies and young children are most often allergic to high protein foods such as milk, eggs, wheat, soyabean products and groundnuts. Sugars and fats do not cause allergic reaction.
Many adults have trouble digesting the sugar in milk.
It isn't a true allergy. Most people with food allergies are allergic to less than 4 foods. Bad reactions to food dyes are rare. They may occur in less than 1 of 100 children and in less than 1 of 500 adults. However, people rarely outgrow allergies to groundnuts, tree nuts, fish and shellfish.