A Good Guide To A Successful Thyroid Diet When there is too much or too small of an amount of thyroid hormone in a person's body, this is usually caused by a disease of the thyroid gland. When there is too much, this leads to hyperthyroidism and when there is too little it is called hypothyroidism. The real question is whether these diets work, are they just a fad or can they really help you to lose weight? Dana answers these questions with a do it...