Although it is common to use your weight on a scale to determine if you are healthy, your weight does not It is as accurate a measure as your body composition. A person can weigh a lot to be perfectly healthy if their lean muscle mass is high. Lean muscle mass is everything that is not fat, such as muscles, bones, organs and water. Losing this muscle mass makes your weight go down, but it raises the amount of body fat in comparison.
Understanding body fat percentage
Your body fat percentage is a measure of body composition. Measuring this percentage takes into account muscle mass. Two people of the same weight may have different percentages of body fat, since one may have more muscles and denser bones, while the other may have more body fat. If you gain body fat, your weight and percentage of fat go up. However, if you gain muscle, your weight increases and your fat percentage decreases. The opposite also is true. You can lose muscle and therefore weigh less, but unless your body fat also changes, this percentage increases.
Measuring your body fat percentage
Knowing your body fat percentage lets you know if you lose body fat or lean mass when you lose weight. There are different ways to measure this percentage. You can find an installation that uses hydrostatic weighing equipment, such as at a university, buy a body fat percentage scale or handheld device or have a professional coach measure you using skinfold calipers. The only way to measure body fat yourself is with a scale or handheld device. These devices send an electrical current through your body and record the time it takes to estimate your percentage of muscle fat. To use one, follow the instructions first to enter any personal information that your specific device asks you to enter, such as your age and gender. Next, place your bare hand in contact with the metal sensor. Stand on a percentage scale of muscle fat with bare feet or hold the handles of a handheld device with your bare hands.
How your body composition changes
You should not assume that you have a healthy amount of body fat just because your weight has remained constant most of your life or because it is within normal ranges based only on weight and height. Body fat increases approximately 1% to 3% every 10 years beginning at age 20, according to the article "Getting a Grip on Body Composition" by Len Kravitz, Ph.D., and Vivian H. Heyward, Ph.D. Older people also lose 2% muscle mass every 10 years. Therefore, you can have the same height and weight at 20 and 60, but you will have more body fat.
Healthy amounts of body fat by age
Your age and gender determine your healthy range of body fat percentage. Women aged 20 to 39 can have 21% to 32% body fat and be healthy, according to the New York University Langone Medical Center. Middle-aged women between 40 and 59 years old should be within a range of 23% to 33%. Women aged 60 to 79 years should be in a range of 24% to 35% body fat. The ranges of body fat for men are lower. Men from 20 to 39 years old should be between 8% and 19%. Men from 40 to 59 years old should have 11% to 21% body fat. Older men are healthy in a range of 13% to 24%.