When doctors measure fat, they use high-tech flab-squeezing instruments called calipers. No access to current sports-medicine technology? Then close the fingers of one hand and make a C with the forefinger and thumb. What do you have? Right, a caliper.

The Test
Tricep pinch. Enlist a partner to hold a ruler. Extend your arm straight in front of you, palm up. Grab the skin on the back of your upper arm (the side facing down) between your thumb and fingers, and gently pull it away from the arm, trying not to pinch the skin too tightly. Have your partner measure the thickness of the skin held between your fingers and thumb (not the distance it’s being pulled out).
Ages 20 to 39: ¾ inch of skin;1/2 inch, good
Ages 40 to 60: 7/8 inch of skin, 5/8 inch, good

What to Do
The best way to cut down your body-fat percentage is to eat a low-fat diet (aim for 30 percent of calories or less) and take up aerobic exercise. The best fat-burning workouts are those that target as many of the body’s muscles as possible. Good bets are rowing, cross-country skiing and hiking.