If you are overweight, you probably know it already and your doctor has probably warned you about its dangers.

However, muscle weighs more than fat, and some people have larger, heavier bones than others. You can be heavy and perfectly healthy if a large percentage of your weight is in bone and muscle. However, if a high percentage of your weight is fat, you are at increased risk for diabetes, heart disease, strokes, some types of cancer and other health problems.

If you're not sure where you stand, use these three simple measures to see whether you should be concerned about excess weight.

Body Mass Index (BMI)

Waist-Hip ratio to determine whether youre an "apple" or a "pear" My "Inch of Pinch" test

The BMI (Body Mass Index) is a standard calculation used by doctors and nutritionists to see if your weight is appropriate for your height. You can find charts and the easy formula to calculate your BMI using a Google search. If your BMI is 30 or more, your statistical risk of death from any cause is increased by 50 to 150 percent. But you need to know more about your body composition. Read on.

Your WAIST/HIP RATIO is calculated by dividing your waist size by your hip size. Use a measuring tape to measure your hips at the widest part of your buttocks. Then measure your waist where it is smallest, usually just above the belly button. Then divide your waist measurement by your hip measurement. Record your result on your Before and After Chart. Women should have a ratio of 0.8 or less; men should be no higher than 1.0. If your ratio is higher than these ideals, you are an apple with excess fat in stored your abdomen.

Finally, here's my "INCH OF PINCH" Test. Ordinary scales tell you your total weight and can help you keep track of weight changes, but they tell you nothing about the composition of your body. If you are exercising and building muscle, you may gain weight in a healthy way. You can buy special scales that estimate your body fat percentage, but they are expensive and not completely reliable. Your doctor may use fat calipers, or send you for an accurate body composition test where you are immersed in water, but you can make a simple calculation yourself using my "Inch of Pinch" test.

Using your thumb and forefinger, grasp the skin 3" to the right or left of your navel. Pinch firmly but not so hard that it hurts. Then slide your hand away without changing the distance between your thumb and forefinger, and see how far apart they are. Ideally you will have pinched about 1/2" inch of flesh. An inch or more in your "pinch" means that your excess body weight is more fat than muscle.

Gabe Mirkin, M.D.

Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in Sports Medicine and three other specialties.

Dr. Mirkin's daily features on fitness have been heard on CBS Radio News stations since the 1970's. He has written 16 books including The Sportsmedicine Book, the best-selling book on the subject that has been translated into many languages. His latest book is The Healthy Heart Miracle, published by HarperCollins.

Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. A Boston native, Dr. Mirkin did his residency at the Massachusetts General Hospital. He has served as a Teaching Fellow at Johns Hopkins Medical School, Assistant Professor at the University of Maryland, and Associate Clinical Professor in Pediatrics at the Georgetown University School of Medicine. He has run more than forty marathons and is now a serious tandem bicycle rider with his wife, nutritionist Diana Mirkin.