Fats are also an important energy source. When the body has used up the calories from carbohydrates, which occurs after the first 20 minutes of exercise, it begins to depend on the calories from fat.
Fat is one of the 3 nutrients (along with protein and carbohydrates) that supply calories to the body. Fat provides 9 calories per gram, more than twice the number provided by carbohydrates or protein.
Fat is essential for the proper functioning of the body. Fats provide essential fatty acids, which are not made by the body and must be obtained from food. The essential fatty acids are linoleic and linolenic acid. They are important for controlling inflammation, blood clotting, and brain development.
Healthy skin and hair are maintained by fat. Fat helps the body absorb and move the vitamins A, D, E, and K through the bloodstream.
Opt for good monounsaturated and polyunsaturated fats, or MUFAs and PUFAs, whenever possible. These heart-healthy fats stabilize cholesterol levels and lower your overall risk of cardiovascular disease when you consume them in place of bad fats.
Monounsaturated and polyunsaturated fats come from vegetable oils, nuts, avocados and cold-water fish, such as salmon and tuna. Bad fats, or saturated and trans fats, raise low-density lipoprotein, also called LDL, cholesterol.
Elevated low-density lipoprotein hardens arteries and raises blood pressure. Over time, you may be more at risk of heart attack and stroke. You need increased levels of high-density lipoprotein to rid your body of excess low-density lipoprotein.
For further reading, see links below:
[healthyeating.sfgate.com](http://healthyeating.sfgate.com/three-functions-fat-body-3402.html
www.nytimes.com