When you’re talking about fat, you’re probably referring to triglycerides. Triglycerides are the main form of fat in the body and in the foods you eat. Each triglyceride is made up of three fatty acids attached to a glycerol molecule, as shown in the following image.
A fatty acid is a chain of carbon atoms that has hydrogen and oxygen atoms attached to it (see the image below). Your body can use the fatty acids in these triglycerides as fuel to power your cells, just as it does with glucose.
Fatty acids come in a number of different chain lengths, which are categorized as short, medium, long, and very long. They can also be classified as saturated or unsaturated. When people talk about saturated and unsaturated fats, they’re talking about the fatty acids that make up a triglyceride molecule.
Now, the really interesting thing is that the three fatty acids in a triglyceride can be in any combination. It’s the different combinations of fatty acids in a triglyceride that give foods their various properties. Take olive oil and coconut oil: Olive oil is liquid and coconut oil is solid! As you can see in the following image, olive oil is made up of mainly unsaturated fats, with a small percentage of saturated fats. Coconut oil, on the other hand, is primarily saturated.
Generally, triglycerides high in saturated fatty acids, such as those found in butter or coconut oil, are solid at room temperature. Triglycerides high in unsaturated fatty acids, for instance those in olive oil and canola oil, are liquid at room temperature. This has to do with the way the carbons in the fatty acid chains are bonded together. In saturated fats, each of the carbons in the chain is bonded to as many hydrogen atoms as possible (in other words, it’s saturated with hydrogen). This allows the atoms to pack together easily and makes them solid. In unsaturated fats, some of the carbons form double bonds between each other, instead of bonding to hydrogen. Take a look at the following image to see the difference between the bonds in saturated and unsaturated fats.
This may seem a bit technical, but it’s important to understand that even seemingly subtle differences, such as the presence or absence of a double bond, the position of the double bond in the fatty acid chain, or the length of the chain, can have a dramatic effect on how your body uses the fat.
Here’s a little more information on the various chain lengths that fatty acids can come in:
Short Chain Fatty Acids
These fats have four to six carbon atoms and are always saturated. Short chain fatty acids are found in butterfat from cows and goats. These fatty acids have antimicrobial properties, meaning they can kill microorganisms such as bacteria or inhibit their growth, throughout the body. They also serve as great sources of energy, as they’re broken down quite readily.
Medium Chain Fatty Acids
These fats have eight to 12 carbon atoms and are found mostly in tropical oils, for instance coconut oil, as well as in butterfat. There are numerous benefits associated with regular consumption of these fats. Like short chain fatty acids, they have antimicrobial properties. They also contribute to the health of your immune system, and studies have shown promising results for their use in treating neurodegenerative disorders including epilepsy, Alzheimer’s disease, and Parkinson’s disease. What’s more, it’s been found that, because of how readily they can be used by the body, the consumption of medium chain fatty acids (compared to long chain fatty acids) can lead to weight loss. Since they are readily used as fuel in your body, they are less likely to be stored.
Long Chain Fatty Acids
Long chain fatty acids have from 14 to 18 carbon atoms and can be saturated, monounsaturated, or polyunsaturated. Examples of long chain fatty acids include monounsaturated fatty acids, such as oleic acid, found in olive oil; polyunsaturated fatty acids, for instance gamma-linolenic acid (GLA), found in plant-based oils; and saturated fatty acids, such as stearic acid, found in beef tallow. It’s been found that when fats (especially long chain fatty acids) reach your small intestine, a message signal is sent to your brain that can inhibit eating. The brain can also put a halt to glucose production when these fatty acids are circulating in your bloodstream.
Very Long Chain Fatty Acids
These fats have from 20 to 24 carbon atoms. Most very long chain fatty acids are very unsaturated, and may contain five or six double bonds.Examples of very long chain fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both of which are heart-healthy omega-3 fatty acids. Now let’s go over the differences between saturated and unsaturated fats in more detail and learn more about their role in your diet.