IgG, or delayed food allergies/intolerances, have been implicated in a wide range of medical conditions, including arthritis, fatigue, weight gain, migraines, eczema, depression, and inflammatory bowel disease. IgG reactions are internal reactions to food that occur hours, or even days after the initial exposure. The food antigen-antibody complexes accumulate and are deposited in body tissues. Once in tissue, these complexes release inflammatory chemicals, which may play a role in numerous diseases and conditions. Unlike immediate anaphylactic IgE reactions, they are not diagnosed through an allergist, but must be tested by your naturopathic doctor.