Subcutaneous fat is found just beneath the skin as opposed to
visceral fat which is found in the
peritoneal cavity. Subcutaneous fat can be measured using
body fat calipers giving a rough estimate of total body
adiposity. This fat aids in the process
homeostasis, by forming a layer of insulation therefore stopping heat loss in the long-term.
The subcutaneous tissue is a layer of fat that lies between the dermis of the skin and underlying fascia. Subcutaneous fat insulates the body, absorbs trauma, and is a reserve energy source.[1] This tissue may be further divided into two components, the actual fatty layer, or panniculus adiposus, and a deeper vestigial layer of muscle, the panniculus carnosus.[2]
The conventional explanation of the environmental factors that drove human evolution was known as the Savannah Hypothesis and was first advanced by Raymond Dart. This postulated that the arboreal existence of the apes was replaced by a move to the savannah in order to hunt animals, even though major adaptations occurred in human ancestors long before the savannahs existed.[3] Several anthropologists, such as Bernard Wood, Kevin Hunt and Philip Tobias, have pronounced the Savannah Theory to be defunct. One of the reasons for the theory's demise is that fat has a much greater weight penalty for a running animal than the hair it supposedly replaced, and yet man carries more fat than other land mammals.
Among humans, men and women require different levels of body fat to be healthy. If a man's body fat percentage falls below about 4%, or a woman's below about 12%, then the person is likely to become seriously ill or perhaps die. However, health effects are seen well before this range. If a woman's adipose tissue constitutes less than 17% of her body weight, she ceases to menstruate.[4] The average human contains ten times as many adipocytes fat cells as would be expected in an average mammal of similar size. From this Elaine Morgan has concluded that at some point in human evolution high minimum standards for fat were established[5]. She contends that the quantity of subcutaneous fat in humans supports the other theory for the early evolution of proto-humans the aquatic ape hypothesis (AAH), though this is still strongly disputed by many researchers. Greater insulation is needed by warm-blooded animals in water than in air.
