Scientists and health care providers have determined that certain percentages of body fat are associated with increased health risk. An easy and inexpensive way to estimate body fatness is to calcualte body mass index (BMI). BMI is an assessment tool used by health professionals around the world. Body fat percentage more commonly is used by fitness professionals to assess fitness level, not health risk.
The Facts
Body mass index (BMI) is an estimate of body fatness. BMI is a weight-for-height ratio used in epidemiological studies. It is the easiest way to estimate body fat or excess body fat tissue and determine an individual's risk of disease.
Body fat percentage is an actual measurement of percentages of fat-free and fat mass in the body. Fat-free mass refers to the weight of non-fat tissue such as muscles, organs and bones. Fat mass is the amount of fat and lipids present in the body.
Disease Risk
A higher BMI and body fat percentage are associated with obesity and increased risk of cardiovascular disease. According to the Obesity Society, obesity affects more than one-third of the American population and is the leading cause of morbidity, mortality and the rise in health care costs.
Measurement
BMI usually is calculated by dividing weight in kilograms by height in meters squared. An easier conversion is weight in pounds divided by height in inches squared multiplied by 704.5.
Various techniques are used to measure body composition, specifically body fat percentage. In hydrostatic weighing, an individual is placed under water to determine fat and fat-free mass. Bioelectrical impedance analysis measures body composition by sending a small current through the body. Skinfold measurement determines body fat by pinching certain sites on the body.
Warning
Individuals with a BMI that falls into the overweight or obese category are at increased risk of certain diseases and health conditions. People with a high percentage of body fat also are at risk of disease. These conditions include hypertension, hyperlipidemia, type 2 diabetes, stroke, osteoarthritis, gallbladder disease, coronary heart disease and cancer.
Considerations
BMI is used by health professionals more often than body fat percentage to asses disease risk. BMI is not a good indicator of body fat percentage. Individuals with increased musculature and skeletal mass may be classified as obese even though they are not. Body fat percentage is the ideal way to measure the ratio of fat to fat-free mass.
References
- "Health Fitness Instructor's Handbook"; Edward T. Howley, B. Don Fanks; 2003
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