Counting calories, working out-and still packing on the pounds? You may have a health issue that's messing with your system. Read on to see if a common condition or widely prescribed drug could be sabotaging your efforts to slim down. POLYCYSTIC OVARIAN SYNDROME(PCOS) "This hormonal imbalance results in an overload of insulin, which promotes fat storage," says Peter Vash, M.D., medical director of Lindora Clinic, a chain of weight-loss centers. Red flags You have light or missing periods, frequent breakouts, and facial hair, and you carry most of your extra weight in your abdomen. Treat it A medication called metformin lowers insulin, and birth control pills provide additional estrogen to counteract testosterone. Keeping your blood sugar steady by eating smaller meals every few hours helps too, as does exercise, which moves sugar into muscles without the need for insulin.     UNDERACTIVE THYROID This gland cranks out T3 and T4, the hormones that control metabolism. When the thyroid doesn't produce enough of either, your body begins to burn fat sluggishly. Red flags You constantly feel tired and cold; have dry skin, thinning hair, a hoarse voice, constipation, or puffiness in your legs and face. Treat it Your doctor will likely prescribe synthetic versions of T3 and T4. Taking supplements that aid thyroid function is also important, says Alicia Stanton, M.D., author of The Complete Idiot's Guide to Hormone Weight Loss. Try these doses daily: 200mcg of selenium, 30mg of zinc, 2mg of copper, and 5,000 IU of vitamin A. STRESS In addition to making your heart race, the surge in adrenaline and cortisol ... More »