It may take up to one year before your thyroid function becomes normal. You should eat a high-fiber diet to reduce the risk of constipation. Also, if you are overweight, you should cut down on your calories and exercise daily (ie, 30 to 45 minutes of aerobic exercise or walking per day). If you have high blood pressure, you should reduce sodium intake. Moreover, if your cholesterol is high, you should eat a high-fiber and low-fat diet.