This invention relates to an effective dietary intervention plan. In one aspect all food is withheld for a period of at least 5 days, except for tropical root crops. In another aspect the invention relates to the treatment of various symptoms, conditions or diseases such as Diarrhea, constipation, congestion, eczema, asthma, fatigue, muscle weakness, tension, and spasms, irritable bowel syndrome, swelling, anxiety, multiple chemical sensitivities, moderate to extensive and moderate to severe symptoms due to food allergies, sensitivities, and intolerances, bloating, pain, headaches, leaky gut, hyperactivity, sleeping difficulties, severe underweight, eating disorders, obsessive, compulsive disorders, panic attacks, sensory sensitivities, Alzheimer's disease, acid reflux, irritability, delayed motor skills, delayed social skills, autism, PDD, infantile spasms, seizures by withholding from the patient for a period of at least 5 days all food except for concentrated forms of concentrated tropical root crops. Preferably the patient is also removed from external environmental sources of allergens. After the initial withholding period new foods may be introduced according to a particular selection and schedule.