Editing Fat (section)

== Biological importance ==
In humans and many animals, fats serve both as energy sources and as stores for energy in excess of what the body needs immediately. Each gram of fat when burned or metabolized releases about nine [[Calorie|food calories]] (37 [[Joule|kJ]] = 8.8 [[kcal]]).<ref name="uksi1996" />

Fats are also sources of [[essential fatty acid]]s, an important dietary requirement. [[Vitamin]]s [[Vitamin A|A]], [[Vitamin D|D]], [[Vitamin E|E]], and [[Vitamin K|K]] are fat-soluble, meaning they can only be digested, absorbed, and transported in conjunction with fats.

Fats play a vital role in maintaining healthy [[skin]] and [[hair]], insulating body organs against shock, maintaining body temperature, and promoting healthy cell function. Fat also serves as a useful buffer against a host of diseases. When a particular substance, whether chemical or biotic, reaches unsafe levels in the bloodstream, the body can effectively dilute—or at least maintain equilibrium of—the offending substances by storing it in new fat tissue.<ref>{{Cite journal |last1=Wu |first1=Yang |last2=Zhang |first2=Aijun |last3=Hamilton |first3=Dale J. |last4=Deng |first4=Tuo |date=2017 |title=Epicardial Fat in the Maintenance of Cardiovascular Health |journal=Methodist DeBakey Cardiovascular Journal |volume=13 |issue=1 |pages=20–24 |doi=10.14797/mdcj-13-1-20 |issn=1947-6094 |pmc=5385790 |pmid=28413578}}</ref> This helps to protect vital organs, until such time as the offending substances can be metabolized or removed from the body by such means as [[excretion]], [[urination]], accidental or intentional [[bloodletting]], [[sebum]] excretion, and [[hair]] growth.

===Adipose tissue===
[[File:Fatmouse.jpg|thumb|The [[obese]] mouse on the left has large stores of adipose tissue. For comparison, a mouse with a normal amount of adipose tissue is shown on the right.]]
In animals, [[adipose tissue]], or fatty tissue is the body's means of storing metabolic energy over extended periods of time. [[Adipocyte]]s (fat cells) store fat derived from the diet and from liver [[metabolism]]. Under energy stress these cells may degrade their stored fat to supply fatty acids and also glycerol to the [[circulatory system|circulation]]. These metabolic activities are regulated by several hormones (e.g., [[insulin]], [[glucagon]] and [[epinephrine]]). Adipose tissue also secretes the hormone [[leptin]].<ref name="hprot0000" />