White fat is normally mostly (75%) stored subcutaneously. Consequently, it also acts as thermal insulation and as protection against mechanical stresses. However, its most important function is as a highly effective energy store. Fats also serve as building material for essential body constituents, such as the myelin insulation of nerve tracts and sheathing of sensitive organs, the kidneys for example are surrounded by a thick layer of fat.
Some white fat is stored abdominally right next to the internal organs. This fat is known as organ or visceral fat. Stored fat releases a series of hormones and hormone-like substances. Due to its close proximity to the bowels visceral fat has a particularly strong influence.
This fatty tissue is distributed differently in men and women. In women it is predominantly subcutaneous in the hip and thigh area and in men it forms mainly visceral fat.
Brown fat represents less than 1% of the body's entire fat percentage. It is located right next to the major vessels (e.g. in the shoulder and neck area), is crossed by a large number of blood vessels and is highly innervated. The mitochondria in the cells of brown fat can convert the energy in the thinly distributed stored fat directly into heat as a result of the respective membrane characteristics. Consequently, this fat acts as an organ for regulating heat in the body.