According to Mayo clinic, one in three American adults is considered obese. An individual is obese if the body has an excessive amount of fat tissue, usually a body fat percentage greater than 32 percent for females and 25 percent for males. Measuring your body fat percentage is a way to measure health risk. Body composition, or body fat percentage, refers to the percentage of fat and nonfat tissues in the body. There is no direct way to measure body fat percentage. Techniques are used to estimate body fat percentage based on the relationship between fat free and fat mass in the body. Body mass index, or BMI, is a number calculated from measuring a person's height and weight. BMI is an easy way to determine body fatness in individuals and is easily calculated with household items.
BMI Body-fat Measurement
Step 1
Step on a scale to determine your weight in pounds.
Step 2
To measure your height, stand next to a wall and place a ruler horizontally on your head. Place a piece of colored tape on the wall where the ruler reaches the wall. Measure the distance from the floor to the piece of tape, in inches, using a measuring tape.
Step 3
Calculate your BMI by dividing your weight in pounds by your height in inches squared. Multiply the numbers by a conversion factor of 703. Standard values exist for BMI. They can be found at such places as the Centers for Disease Control and Prevention website.
Example: Measure the BMI of a female weighing 175 pounds and 66 inches tall.
BMI = [175/(66)2] x 703
BMI = [175/4,356] x 703
BMI = [.0401744] x 703
BMI = 28.2
Skin-fold Caliper Body-fat Measurement
Step 1
Purchase inexpensive skin-fold calipers from a local sporting goods store. The measurement on the skin-fold calipers should be in millimeters.
Step 2
Pinch the skin at the back of the arm. Clamp the calipers around the skin. Release the handle of the calipers and measure the fat on the site by reading the numbers on the calipers. Record the number from your calipers for triceps on your sheet of paper.
Pinch the skin 1 inch above the hip bone. Clamp the skin-fold calipers around the site and read the numbers from the caliper. Record the number for your calipers for your hip on your sheet of paper.
Pinch the skin at the side of the belly button. Place two fingers next to the belly button. With the other hand, pinch a diagonal fold of skin. Place the calipers on the skin fold and read the numbers from the calipers. Record the number for abdominal measurement on your sheet of paper.
Locate the middle portion of your thigh. Midway is between the crease in the groin and the top of the knee. At the halfway point, pinch the skin in a diagonal fold. Place the calipers on the skin fold and read the numbers. Record the number on the sheet of paper for thigh measurement.
Step 3
Repeat measurements at all four sites for accuracy. The measurements should be within 2 millimeters of each other. If the measurement is greater or less than 2 millimeters, measure the site again. Take the average of the two measures for each site.
Step 4
Add the sum of measurements from all sites and plug the information into the following formula for men and women.
Formula for men:
Body-fat Percentage =
0.29288(sum of measurements) - 0.0005(sum of measurements)2 + 0.15845(age) - 5.76377
Formula for women:
Body-fat Percentage =
0.29669(sum of measurements) - 0.00043(sum of measurements)2 + 0.02963(age) + 1.4072
To determine fat weight and lean weight, use the following formulas.
Fat Weight = Body-fat % X Scale weight
Lean Body Mass = scale weight - Fat weight
Measure Body Fat Using Body Fat Scale
Step 1
Purchase a body-fat scale from your local sporting goods store; some major retailers carry them as well. Read the directions for your particular scale before use.
Step 2
Perform the skin-fold test using the scale first thing in the morning after emptying your bladder and before having anything to drink. Remove all lotions and creams from the body.
Step 3
Turn your scale on. Set the scale for men or women and add additional information as needed. Tap the scale with your foot to ensure that it's ready for use. Wait for the scale to say ready or turn green. Stand on the scale barefoot and place your feet on the metal plates on the scale.
Step 4
Scales usually beep to indicate that the reading is finished. Read the information on the display screen. Record the information in your workout journal or wherever you keep track of your progress.
Tips and Warnings
- You'll need a friend to help with measuring body fat utilizing the calipers.
- BMIs in excess of 25 are considered overweight. BMIs in excess of 30 are considered obese. Obese individuals are at increased risk of developing cardiovascular disease.
Things You'll Need
- Scale
- Measuring tape
- Body-fat scale
- Skin-fold calipers
References
- "Health Fitness Instructor's Handbook"; Edward T. Howley, B. Don Franks; 2003.
- Mayo Clinic: Obesity
- Lee Hayward: How to Measure your Bodyfat Percentage
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