Whether you're want to lose weight, practicing for fitness or just keeping track of your physical health, the trusty bathroom scales will help you monitor your progress. But weight is just one factor in determining your quality of life. It's more vital to know your system composition – your muscle mass and the amount fat you're carrying.

It’s debatable whether you must know your extra fat in the first place. True, weight can be deceptive given it doesn’t indicate the amount is from fat and the amount is from muscle. But there’s no widely accepted standard for ideal unwanted fat; it all depends on age, sex, fitness and ethnicity. According to some experts, a “healthy” range is 23 to 33 percent for middle-aged women, 11 to 21 percent for middle-age men or longer to 35 percent for older along with 24 percent for older men. Athletes normally have much less unwanted fat.