10 Things That Affect Your Weight Besides Food and Exercise

A doctor checks a woman's thyroid gland. Hypothyroidism can cause you to gain weight. BSIP/UIG via Getty Images

Your butterfly-shaped thyroid gland sits in the front of your neck. This little-heralded gland churns out hormones that regulate your metabolism. If it shoots out too many in your bloodstream, you may develop hyperthyroidism. If it shoots out too few hormones, you may get hypothyroidism. The latter is the more common of the two problems. Side effects include sluggishness, feelings of coldness, slower heart rate, feelings of exhaustion and depression, a swelling of the neck and weight gain. With both hypothyroidism and hyperthyroidism, your hair may fall out [source: WebMD].

Women, especially those over 60, are more likely get hypothyroidism than men — and it tends to run in families. It is often caused by Hashimoto's disease, an autoimmune disorder where the body attacks the thyroid gland. A simple blood test measuring the amount of TSH, or thyroid stimulating hormone, in your system can diagnose whether you suffer from a thyroid condition. If you have any reason to believe you do, ask your physician to conduct this blood test, which is fairly common. Look also at your neck in the mirror as you tip your head back and swallow some water. If you see a bulge below the Adam's apple, you might have a thyroid condition [source: WebMD].