Standard body weight scales provide a measure of total weight, but don't determine the lean-to-fat ratio of that weight. Standing on most scales can tell you only if you weigh more than the average person, but not if that weight is fat or muscle. Based only on scale weight, a 250 pound athlete with 8% body fat may be considered "overweight" by a typical weight chart. Such charts are not a good indications of ideal body weight for general health or for athletic performance. body fat testing