Essential fat is the body fat or adipose tissue a person has that is essential to a number of bodily functions, from forming reproductive tissue to aiding in the absorption of vitamins consumed in food. It is differentiated from subcutaneous body fat, or body fat that is stored under the skin for future energy use, as essential fat can generally not be used for energy except in cases of severe malnutrition. Together, essential and stored fat when divided in pounds from a person’s total body weight make up that person’s total body fat percentage. In women, this fat makes up roughly nine to 12 percent of total body weight, while in men it accounts for approximately three to five percent.
Distributed throughout the body’s systems, essential fat is found in nearly every part of the body. It is found in bone marrow, forming the membranous sheaths enveloping individual nerves as well as those lining the brain, distributed throughout muscle tissue, and lining the walls of organs ranging from the heart and lungs to the intestines. Additionally, this kind of fat is a major component of reproductive tissue, particularly in women who carry it in breast and uterine tissue. This accounts for the extra weight in the fat stored in women’s bodies.
Essential fat is distinguished by its role in the constitution of bodily structures rather than by an involvement in metabolic processes. In other words, it is not used as an energy source when the body’s caloric expenditure exceeds its caloric intake, as is stored body fat. Instead, it is used as a sort of building material for many of the body’s tissues. As such, this fat is not burned off during weight loss the way subcutaneous fat is, and is considered not only healthy to possess but necessary for the body to function.
Body composition testing techniques such as caliper testing, underwater weighing, and more modern techniques like dual energy X-ray absorptiometry take into account total body fat percentage as a portion of total body weight. For instance, if a woman’s total fat percentage is 25 percent and nine to 12 percent is from essential fat, then the remaining 13 to 16 percent comes from stored body fat. If she weighs 140 pounds (63.5 kilograms), 35 pounds (15.88 kilos)come from fat with anywhere from 13-17 of those pounds (5.7-7.7 kilos)contributed by essential fat.
Considering this, it is impossible to have zero body fat. Even the leanest of athletes, with females having as little as 14 percent total body fat and males as little as six percent, will typically have a few pounds of subcutaneous fat on top of their essential fat percentage. The recommended range of total body fat for healthy women is typically 18 to 24 percent and for men is 10 to 17 percent, with athletes coming in at 14 to 18 percent and six to 10 percent, respectively.
