Edema is a medical condition that results when you have too much water in your body. The symptoms of edema are swelling around the joints, puffiness of the muscles of the legs and arms, and weight gain.  Edema may be the result of eating foods that cause water retention. Other possible causes are congestive heart failure and inefficient activity of the blood vessels that restricts blood flow leading to increased blood pressure (remember, your blood is 90 percent water).