All you used to need was a full-length mirror or the bathroom scale to tell if you were overweight.

Now there is a $300 device called the Futrex 1000 that measures body fat."Body fat absorbs infrared light. Lean mass - like bone and muscle - reflects light," says Bob Rosenthal of Futrex Inc. "By plugging in your height and weight, the machine gives you the percentage of body fat in your body."

While taking routine readings may make you more prudent in your calorie intake, better you should skip the morning doughnuts, buy a $20 scale and do 10 sit-ups every day.

The device from Futrex Inc., Hagerstown, Md., is available through Sporting Edge catalog, 1-800-468-4410.