Types of Fat and Their Differences

There are four main types of fat found in the human diet. They are:

• Saturated Fat
• Monounsaturated Fat
• Polyunsaturated Fat
• Trans Fat

Some of these fats are seen as healthier than others, and one of these fats is actually man made and has been shown through tests and trials to be very unhealthy for you. But before we can get into all that, let's first talk a bit about why fats are named the way they are. What does saturated and unsaturated mean anyway?

The picture to the right illustrates the main difference between the different types of fat. You'll notice that fats are comprised of atoms of Oxygen, Hydrogen, and Carbon. These are the same three atoms that make up the various sugars. A saturated fat is one whose carbon atoms are all completely surrounded by hydrogen atoms, plus the two oxygen atoms at the end. An unsaturated fat is one with one or more carbon atoms not completely surrounded, and thus forming a double bond. This is the difference between a saturated fat and an unsaturated fat. Saturated fats are completely saturated with hydrogen atoms, as much as they can handle.

A monounsaturated fat is a fat with only one pair of carbon atoms missing their hydrogen atoms. A polyunsaturated fat is one with multiple double bonded carbon atoms that are each missing hydrogen atoms. In general, the more hydrogen atoms a fat is missing, the healthier the fat is to the body. This is a very general statement however and is not true in all cases.

Polyunsaturated fats are generally seen as healthy for the human body. A good example of a polyunsaturated fat is the Omega essential fatty acid linoleic acid, pictured above. You'll notice that the first pair of double bonded carbon atoms happens at the 6th place, making it an Omega 6 essential fatty acid. There are 3 types of Omega fatty acids, Omega 3s, Omega 6s, and Omega 9s. They get their name from where the first pair of double bonded carbon atoms happens. Omega fatty acids are therefore either polyunsaturated or monounsaturated fats.

The main general reason why polyunsaturated fats are healthier for you is mostly due to the carbon pairs. Each time there's a double bond of carbon pairs in the molecule, the molecule of fat bends, as you can see from the picture to the right. This has one major effect. Polyunsaturated fat molecules take up more room than saturated fat molecules. The bending in the polyunsaturated fat makes them harder to stack together than straight molecules of saturated fats. This makes them less dense and it also gives them a lower melting point. Some people have observed that fats with melting points lower than the temperature of the human body are healthier because they won't become solids in the body and clog the arteries. Fats that are more dense and which have a higher melting point are not only harder for the body to digest, they also generally raise levels of bad LDL cholesterol.

Trans fats, also known as hydrogenated fats, are created when hydrogen is forced into fats at high pressure in order to make them lighter and fluffier. Because this process eliminates the double bonded carbons, it can only be done to monounsaturated fat and polyunsaturated fat. Saturated fats already contain as many hydrogen atoms as they can carry, so the process of hydrogenation doesn't work on them. Of all fats, many people consider trans fats to be the most dangerous. They cause an elevated risk of heart disease because of the fact that they lower HDL cholesterol and raise LDL cholesterol. Most experts agree that trans fat consumption should be kept to a minimum if possible.

Some fats are combined together, generally for the purpose of more efficient storage. When fatty acid molecules are bonded to a glyceride molecule, multiple molecules of fat are able to be combined together into a single molecule. The picture to the right is an example of a triglyceride, which is the most common form of fat storage in the body. The tri, as you can see, stands for three molecules of fatty acids, bound together by a glyceride molecule. A diglyceride molecule is two fatty acid molecules combined by a glyceride molecule, and a monoglyceride is a fatty acid molecule combined with a single glyceride molecule. Triglycerides are the body's preferred fat storage method, because of how efficient it is, and triglycerides are routinely created by the liver and then stored in the adipose tissue of the human body beneath the skin, where they await a signal to be released back into the bloodstream.