Measuring and Testing Bodyfat

BODYFAT TESTS MEASURE:

1. Whole body weight
2. How much of your body weight is fat weight
3. How much of your body weight is fat-free weight (FFW)
• This includes bone, muscles, organs and fluids

The result is a percentage that tells you what percent of your body weight is fat.

TYPES OF BODYFAT:

1. Essential Fat

Essential fat is necessary for the normal physiological functioning of the body. It's stored in the bone marrow of organs like the heart, lungs, liver, spleen kidneys, and intestines, and in the tissues of the spinal column and brain. The body needs a small amount of this fat for insulation, cushioning between the body parts and vital organs, and maintaining the functioning of the body systems. A healthy amount of essential fat is in the range of between 3 and 7 percent of the total body weight of men and between 8 and 15 percent of the total body weight of women.

2. Storage Fat

Storage fat makes up the remainder of our fat reserves. This is the type of fat most of us are trying to lose. Storage fat accumulates in the fatty tissues around the organs and in fat deposits beneath the skin. A certain amount of storage fat is necessary for maintaining health, appearance, and good nutrition. However, too much is very detrimental to your health, not to mention your appearance! This may be the reason that liposuction is America's most popular surgery (physicians performed almost 300,000 procedures in 2000, an increase of over 300 percent since 1992). It is important to realize, however, that liposuction doesn't work well in people with a lot of abdominal fat because much of the fat lies in the abdominal cavity, which the procedure cannot treat. It seems to work best on individuals with an already low bodyfat percentage just trying to improve their "problem areas."

TESTS FOR BODYFAT:

1. Skinfold Measurements

Skinfold measurements are based on the belief that approximately 50 percent of total bodyfat lies under the skin, and involves measuring the thickness of the skinfolds at specific sites using a specially-designed caliper. Remember that the validity of the results greatly depends on the tester and calipers.

• Pro:
• Inexpensive
• Accessible
• Reliable
• Valid
• Con:
• May require a skilled tester
• Invalid for obese people


2. Hydrostatic Weighing

This test involves suspending yourself under water seated in a chair attached to a scale, usually in a pool or tank of water. The tester compares your normal body weight to your underwater weight to calculate your body density. Then your lungs' residual volume is either taken directly or estimated from a formula (not as accurate) to help determine bodyfat percentage.

• Pro:
• The "gold standard" in validity
• Very reliable
• Con:
• Time
• Preparation/Equipment/Location
• Expense


3. Bioelectrical Impedance

This test is based on the principle that the conductivity of an electrical impulse is greater through lean tissue than through fatty tissue. The subject must lay still, with electrodes placed on the wrist and ankles.

• Pro:
• Fast
• Easy
• Con:
• Expense


4. Body Mass Index

Body Mass Index, or BMI, uses calculations based on bodyweight and height. Since BMI uses total bodyweight, and not estimates of fat and fat-free mass separately, it does not discriminate between the overfat and the athletic, more muscular type. Therefore, BMI should ideally be used in conjunction with other body composition assessments.

• Pro:
• Fast
• Provides useful data
• Con:
• Does not work on:
• Persons younger than 18
• Frail or sedentary elderly people
• Competitive athletes
• Bodybuilders
• Pregnant or nursing women