Hashimoto's disease affects the body's immune system which in turn affects the thyroid gland. The inflammation thus resulting causes hypothyroidism, where the thyroid gland becomes underactive. It is better for a Hashimoto's patients to have a high-fiber, low-fat diet. More than 25 grams of fiber per day should be included in the diet. As fiber has ability to absorb water, it helps material to quickly pass via the gastrointestinal system. This prevents from exposure to toxins. The fiber should contain both insoluble and soluble fiber. A low-fat diet helps to control cholesterol, which can maintain the overall health of the patient.