Adipose tissue, or fat, is essential for the body to function properly. According to the American Council on Exercise, women need a body fat percentage of 10 to 12 percent for the tissue to adequately protect the body, regulate temperature, provide insulation, produce sex hormones and supply enough fuel to carry out activities.
Dangers arise when the body stores too much fat. The American Heart Association states that a higher body fat percentage can lead to greater risks for developing diabetes, strokes, gallstones, high blood pressure, cholesterol and heart disease, even among women categorized in the “normal” range for weight and body mass index (BMI). A study released in the American Journal of Clinical Nutrition found that levels of inflammation, which indicates a future risk for obesity, heart disease and metabolic disorders, correlated with a woman’s percentage of body fat and not with body weight or BMI.
Recommended Body Fat Percentages
The American College of Sports Medicine (ACSM) states that a range of 20 to 35 percent in women under 40, or between 25 and 38 percent in women over 40 is considered a healthy range. To meet fitness standards, women under 40 should aim for 16 to 28 percent, or 20 to 33 percent if over 40.
The American Council on Exercise (ACE) lists a range of 25 to 31 percent as acceptable, with individuals falling in the 14 to 24 percent range meeting the athletic and fitness classifications.
Studies indicate that most women exceed the body fat percentage recommendations set by ACSM and ACE. According to the National Health and Nutrition Examination Survey, the average percentage body fat in American females ranged from 32.0 percent at age 8 through 11 years to 42.4 percent at age 60 through 79.
Measuring Body Fat Percentages
Because of their cost and convenience, body fat scales have become one of the most popular ways to determine body composition. The scales use bioelectrical impedance, which involves passing an electrical current through the body and measuring resistance from the dense tissue. Other methods of measuring body fat percentages include mathematical formulas, skin fold measures and underwater weighing.
Factors such as the person’s hydration and quality of equipment can impact the accuracy of readings. Even the most reliable techniques report an error of at least 3 percent, meaning that a person whose body fat is calculated to be 23 percent could actually be as low as 20 percent or as high as 26 percent.
Excess Fat in the Waist
According to the National Institutes of Health Weight-Control Information Network, the way the body stores excess weight can be a health risk. Women who carry fat around the waist are more likely to develop health problems than those who carry it in their hips and thighs. Women whose waists are more than 35 inches (measurement taken around the abdomen just above the hip bone) could have a higher disease risk than those with smaller waists.
Body Fat Percentage Compared to BMI
The government and many health organizations use BMI to evaluate an individual’s weight. The formula assesses weight relative to height. This number is figured by dividing weight in pounds by height in inches squared and then multiplying by 703. A score between 19 and 25 is in the healthy range; over 30 is considered obese.
Since BMI is based on numbers and not body composition, it is not as reliable as body fat percentage for providing an accurate assessment of health and fitness. For example, a very muscular person could fall into the overweight or obese category when in fact they are not.
How to Lower Body Fat Percentage
Burning stored fat and carbohydrates is the most effective way to decrease the percentage of fat in the body. This can be achieved through aerobic activities such as running, biking, swimming, dancing, inline skating, stair stepping, elliptical training and rowing, while working at 50 to 80 percent of the maximum heart rate.