You may be obsessed with the number on the scale, but your weight alone is not a good indicator of your health. Body fat percentage and body mass index are both measures used to more accurately assess health risks. Knowing the recommended ranges for body fat percentages and BMI can help determine your risk of obesity-related health conditions, such as diabetes and certain types of cancers.
Measuring Body Fat Percentage
There are a number of different methods used to measure body fat percentage, including skinfold testing, bioelectric impedance analysis and hydrostatic weighing. Skinfold testing is fairly easy and accurate, but requires a trained technician. Bioelectric impedance analysis and hydrostatic weighing are also accurate, but are clinical tests usually conducted in a laboratory. The Navy has developed a mathematical formula for both men and women to determine body fat percentage that requires measurements of your neck and abdomen for men, and neck, waist and hips for women.
Measuring your BMI is a lot simpler than measuring your body fat percentage because it's one formula and requires your height and weight. You can determine your BMI by multiplying your weight in pounds by 703, then dividing that number by your height in inches, and dividing the new number again by your height in inches. For example, a 72-inch tall man weighing 200 pounds has a BMI of 27.
Body Fat Ranges
The recommendations for body fat percentages are based on gender and age. For men, healthy body fat percentage ranges from 7 to 25 percent, and for women 16 to 33 percent. The older you are, the higher your body fat percentage range. For example, the recommended body fat range for a 35-year-old man is 12 to 21 percent, and for a 65-year-old man it is 17 to 25 percent. Not only do body fat percentages greater than the recommendations increase your risk of illness, but so do body fat percentages less than the recommendations. Not having enough fat can disrupt normal body functions, body fat in men should not fall below 5 percent, and in women it should not fall below 15 percent.
BMI measurements are divided into five categories. The recommended healthy BMI range is 18.5 to 24.9. A BMI less than 18.5 means that you are underweight, and a BMI that ranges from 25 to 29.9 means you are overweight. Obesity is indicated if your BMI is 30.0 to 39.9, and extreme obesity if it is greater than 40. While BMI is a good indicator of health risk, it does not distinguish betwee fat and lean body mass, so in some cases is not a helpful tool. Bodybuilders, for example, have a high BMI but low body fat percentages.
- American College of Sports Medicine: Measuring and Evaluating Body Composition
- MedlinePlus: Body Mass Index
- University of New Mexico: Getting a Grip on Body Composition
- Vanderbilt University: Health & Wellness: Body Fat Percentage
- Navy Physical Readiness Program: Guide 4 The Body Composition Assessment (BCA)
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