Why Your Body Needs (Some) Fat
What is Fat?
Fats are a combination of fatty acids and glycerol molecules. Fatty acids are carbon-hydrogen chains with an acid at the end; glycerol is a carbon-hydrogen bond that contains hydroxyl groups (-OH). And even though most people try not to eat any fat (except maybe omega 3 fatty acids), it is not necessarily fat that makes you, well, fat.
When you ingest more calories than you burn, whether it is in the form of fats, proteins or carbohydrates, fat tissue will be produced. So even when you only eat fat free products, you can still increase your waist size, because those products may contain a lot of calories, since the fat is replaced by sugars. So if you consume more calories than you burn in a day, and do this consistently, you will gain fat tissue, regardless of what it exactly is you eat.
The Need for Fat
Your body, however, needs fat. It is used to build tissue and hormones and to isolate your neurons. Furthermore, it is a source of stored energy, shapes your body, reduces heat loss through isolating your organs and muscles and reduces impact on your body and organs (like a natural airbag). It also contributes to keeping your tissues moist and your joints lubed.
Furthermore it forms a liquid barrier through oils on your skin. This barrier is based on the principle that oil and water don’t mix. Oil is a liquid fat and your skin produces oils that are excreted through your pores and subsequently form a layer on one’s skin that makes sure you don’t dehydrate on a hot day or swell up in the shower.
The membranes of all your cells contain lipids, which constitute a boundary between the metabolism in the cell and the liquid outside of the cell. Fats are also involved in what happens inside the cell. Hormones are products of a metabolic process that takes place inside cells. Insulin, for example, the hormone that regulates the glucose levels in the blood, is produced in the pancreas, and fat molecules are an important part of the hormone.
Thus, Fat is not (that) Evil
So, yes, fats are an important nutrient, but there are good fats and bad fats. Food articles contain three sorts of fat: triglycerides, phospholipids and sterols. The body also produces lipoprotein, a bond between proteins and fats that is involved with the transport of cholesterol through the body. In conclusion, fats are not evil, but, as with most nutrients, don’t overdo it.