Your Body
Body composition is the percentage of bone, fat, water and muscle in the human body. Healthy body compositions have a low percentage of body fat and a higher percentage of fat free mass – this includes your muscle, bones and organs. Doctors use your body composition to measure where you are at as far as health and fitness. Many times your body composition will be measured at the beginning of your weight loss journey or a fitness program. This allows you to track your progress throughout these programs.
Define Body Composition
Everybody is made up of two types of body mass: body fat and fat free mass.
Body fat is found in the muscle tissue under the skin and around your organs. Not all fat is bad, you need some fat which is called essential fat. This fat stores energy, helps to protect your organs and also is important in regulating your bodies hormones.
Fat free mass is just as it names suggests, and contains no fat. Fat free mass includes your bones, water mass, muscles, organs and tissues. Another name for fat free mass is lean tissue. Unlike body fat, lean tissues are constantly active and burning calories for energy.
Doctors are able to measure body compositions by your body fat percentage. Your body fat percentage tells how much of your weight is just body fat. There are normal ranges for both men and women across the board. When you weigh yourself on a normal scale, you will not be able to tell how much of your body is fat and how much is not fat. In order to know your body composition you can take simple measurements and enter them into a body fat percentage calculator.
Your Body Fat Percentage
Healthy Body Composition
The American Council on Exercise (ACE) gives these ranges of values for different populations:
ACE Body Fat Percent Norms for Men and Women
| Description | Women | Men |
| Essential Fat | 10% to 13% | 2% to 5% |
| Athletes | 14% to 20% | 6% to 13% |
| Fitness | 21% to 24% | 14% to 17% |
| Acceptable | 25% to 31% | 18% to 24% |
| Obese | over 32% | over 25% |
Many athletes have a lower than normal body fat, especially in sports like running and cycling. But in most cases, having a really low body fat percentage is considered a health issue. This can be a sign of an eating disorder. The same is true on the opposite end of the spectrum. Having a high amount of body fat is not good for your health either. If you are looking to improve your body composition you can gain lean body mass by building your muscle mass. Diet and exercise is key.
Measuring Your Body Composition
There are a couple different ways to measure your body fat percentage.
Bioelectrical Impedance: This method is used by handheld units and by BIA body fat scales you step onto like a regular scale. A small electrical current passes through your body. Fat, water and lean tissue impede the current difference to give the reading. Many scales are sold for home use and no special training is required. Some scales, like the Fitbit Aria 2, even sync with your fitness tracker so that you can see how changes to your daily activity and diet affect your weight.
Skinfold Measurements: This method is often used by fitness trainers or as part of a weight loss program. Calipers are used to take measurements at different parts of your body.
DEXA Scan (dual energy x-ray absorptiometry): This scan is performed in a medical setting and can also be used to check for bone density.
Hydrostatic Weighing: It’s harder to find this gold standard for body fat measurement that involves being dunked in a water tank.
Body Fat Calculators: There are calculators like the one above that use various body measurements to estimate body fat percentage.
Factors that Affect Body Composition
Unfortunately your body composition can also be influenced by things that you cannot control.
Age: As you get older, you lose muscle mass if you are not maintaining it with enough weight training. As a result, you will have a slower metabolism.
Sex: Women naturally have more body fat than men because it is their body preparing for pregnancy and nursing.
Genes: Your genes help decide whether you naturally have a tendency to retain fat or whether you are naturally lean. It will also determine where you store your fat.
Hormones: This can influence your water retention and body composition.
Changing Your Body Composition
If you have a high body fat percentage you want to try and get it down in order to improve your health and wellbeing. You decrease your risk of disease with a lower body fat percentage. Combing diet and exercise can help you achieve and maintain an ideal body fat percentage.
Body composition and body fat are important when you are on a weight loss program. You could be successful in losing fat and gaining muscle without seeing your weight go down. Tracking your weight loss and fitness efforts with body composition measurement is a good way to see your progress.
