Brown fat, also called brown adipose tissue, is a special type of body fat that is turned on (activated) when you get cold. Brown fat produces heat to help maintain your body temperature in cold conditions. Brown fat contains many more mitochondria than does white fat. These mitochondria are the "engines" in brown fat that burn calories to produce heat. Brown fat has generated interest among researchers because it appears to be able to use regular body fat as fuel. In addition, exercise may stimulate hormones that activate brown fat. It's too soon to know whether brown fat's calorie-burning properties can be harnessed for weight loss. In the meantime, be sure to include physical activity in your weight management plans.
Essential fat is necessary to maintain life and reproductive functions. Women have higher body fat and essential body fat percentages relative to men for any given level of fitness. This difference is attributed to physiological differences, such as hormones, ovulation and childbearing. The percentage of essential fat is 4–5% in men, and 10–13% in women.
Storage body fat consists of fat accumulation in adipose tissue. The main role of adipose tissue is to store energy in the form of lipids, although it also cushions and insulates the body, protecting internal organs in the chest and abdomen. While some storage body fat is needed, excess accumulation of fat can be harmful.