One of the most frustrating symptoms of hypothyroidism is the inability to lose weight, even when calories are low and hours logged on the treadmill are high. Hypothyroidism slows the body’s metabolism and its ability to burn fat. It also prevents our cells from responding to lipase, an enzyme that metabolizes fat. The inability to burn fat then contributes to fatigue and cravings for sweets and starchy foods—the very foods that make one fat. Also, since hypothyroidism hinders human growth hormone, building muscle through exercise is difficult if not impossible when hypothyroid.