In healthy humans, rapidly-absorbed carbohydrates cause a greater and more prolonged rise in plasma GIP relative to slowly-absorbed carbohydrates [203], and the rise in plasma GIP following ingestion of a standard meal is decreased by co-ingestion of guar gum [344] and lower in individuals with tropical malabsorption [341] or with coeliac disease [345] relative to healthy controls. The gene discussed is GIP; the disease is celiac disease.