 Allergy testing is not particularly effective in predicting which foods are driving the disease process.Various approaches have been tried, where either six food groups (cow's milk, wheat, egg, soy, nuts and fish/seafood), four groups (animal milk, gluten-containing cereals, egg, legumes) or two groups (animal milk and gluten-containing cereals) are excluded for a period of time, usually six weeks.Endoscopy is required to measure the response to the dietary measure.