What is Fat?
[[File:Fatmouse.jpg|right|thumb|The [[obesity|fatty]] [[mouse]] on the left has a lot of [[adipose tissue]]. In many animals, adipose tissue is used to store energy. For comparison, a mouse with a normal amount of adipose tissue is shown on the right]] {{Hatnote|Fat can also refer to a [[obese]] person.}} '''Fat''' is one of the three main types of [[macronutrient]]s.<ref>The others are [[proteins]] and [[carbohydrates]].</ref> Fats are found in many foods. They are made of [[macromolecule]]s called [[lipids]]. Lipids are based on long-chain [[fatty acid]]s. Some of these are [[essential fatty acids|essential]] because the body cannot make them. == Types and functions == There are three different types of fats: Unsaturated fats, Saturated fats, and Trans fats.<ref>{{Cite web|last=|first=|date=9 June 2014|title=Types of Fat|url=http://www.hsph.harvard.edu/nutritionsource/types-of-fat/|website=Harvard T.H. Chan School of Public Health|publisher=|accessdate=16 May 2016}}</ref> === Unsaturated fats === Unsaturated fats are liquid at room temperature. They are considered useful fats because they can improve blood [[cholesterol]] levels, and ease heart rhythms. Most vegetable oils are liquid at room temperature and have unsaturated fats. There are two kinds of unsaturated fats, Mono-unsaturated fats, and polyunsaturated fats.<ref>{{Cite web|last=|first=|title=Types of Fats|url=https://www.nlm.nih.gov/medlineplus/ency/patientinstructions/000104.htm|website=Medline Plus - Trusted Health Information for You|publisher=|accessdate=1 June 2016}}</ref> It is commonly found in [[avocado]]s, [[nut]]s, [[peanut]]s, [[seed]]s, wild fish, and [[olive oil]]. For polyunsaturated fats, it is recommended to have an omega-3 to omega-6 ratio of 1:1.<ref>{{Cite journal|last=Simopoulos|first=A. P.|date=October 2002|title=The importance of the ratio of omega-6/omega-3 essential fatty acids|url=https://pubmed.ncbi.nlm.nih.gov/12442909/|journal=Biomedicine & Pharmacotherapy = Biomedecine & Pharmacotherapie|volume=56|issue=8|pages=365–37