Hypothyroidism
If your thyroid (the butterfly-shaped gland in the front of your neck) is not making enough thyroid hormone, you’re probably feeling tired, weak, and cold, and gaining weight. Without enough thyroid hormone, your metabolism slows, making weight gain more likely.
Even a thyroid functioning at the lower end of the normal range might cause weight gain. Treating hypothyroidism with medication may reverse some of the weight gain.
