Broadly speaking, two types of body fat exist: essential fat and storage fat. The body cannot be “fat free.” Fat is a normal, necessary component of cells. Cholesterol and triglycerides, for example, are lipids that are required for life but in excess can produce major problems in blood vessels, the heart, and elsewhere. This is essential fat and, in the normal, healthy adult female, makes up about 12% of body weight and in men about 3%. Although unfair, this is the way the body is made.
Storage fat is a way the body stores or stockpiles energy for future use. It is under the skin and inside the body around many organs. Everyone needs a certain amount of storage fat, but an excess is unhealthy. Storage fat in the male is around 12% and in the female is around 15% (yes, still unfair). The ideal percentages of body fat for the population are as follows.
• Up to 30 years old: 14% to 21%
• 30 to 50 years old: 15% to 23%
• Over 50 years old: 16% to 26%
• Up to 30 years old: 9% to 15%
• 30 to 50 years old: 11% to 17%
• Over 50 years old: 12% to 29%
The American Council on Exercise has determined that acceptable “fitness” levels of body fat are 21% to 24% for women and 14% to 17% for men. Because this is a bit complicated, it is probably best to stick with the BMI and weight, age, and height when trying to determine what is a healthy weight.