ADHD diets evolved from the theory that certain substances in a patient’s diet may cause or worsen the symptoms of the disorder. According to this theory, these substances may cause allergic reactions or yeast infections — which may lead to the development of ADHD — and eliminating these substances may help patients manage their symptoms. These substances include artificial food additives, preservatives and sugar. Common whole foods like milk, nuts, wheat, fish, and soy may also be eliminated in these diets. Keep in mind that ADHD diets are still relatively controversial, as many doctors prefer treatments proven by controlled trials. Trials that test elimination diets are often more difficult to evaluate than medication.