Noun
allergic reaction to a substance ingested in food
Source: WordNetThe next day, Greg is so large that he cannot even ride the car to school because he can't fit in the car. His parents believe this to have been caused by a food allergy and resolve to take him to the doctor later. R. L. Stine
Food allergy is a problem that affects a significant part of the population, but is more prevalent in infants and children. Source: Internet