The Four Types Of Fat
Author: Scott Kustes
There are four high-level categories that all fats fall into. You've heard of all of these: monounsaturated, polyunsaturated, saturated, and trans fats. There are two configurations for fats, known as cis and trans. Don't ask me why those names were chosen over "bent" and "straight"…you know how those science types are.
There are four high-level categories that all fats fall into. You've heard of all of these: monounsaturated, polyunsaturated, saturated, and trans fats. There are two configurations for fats, known as cis and trans. Don't ask me why those names were chosen over "bent" and "straight"…you know how those science types are.
Let's explore the four types a bit, so we have an understanding of what we're talking about. Here's an image of three molecules that I'm going to refer to a couple times, so keep it handy.
Saturated Fat
Saturated huh? Exactly what is it saturated with? Hydrogen. Saturated fats refer to fats in which all carbon atoms are bonded to hydrogen atoms (as opposed to having a double-bond connection to another carbon atom). So looking at the handout (click the link above if you closed that picture that I told you to keep handy…you kids never listen), you can see that the top molecule has no double bonds between carbon atoms and is therefore saturated with hydrogen (i.e., holding as many hydrogen atoms as possible).
Saturated huh? Exactly what is it saturated with? Hydrogen. Saturated fats refer to fats in which all carbon atoms are bonded to hydrogen atoms (as opposed to having a double-bond connection to another carbon atom). So looking at the handout (click the link above if you closed that picture that I told you to keep handy…you kids never listen), you can see that the top molecule has no double bonds between carbon atoms and is therefore saturated with hydrogen (i.e., holding as many hydrogen atoms as possible).
Monounsaturated Fat
So then if a saturated fat is holding as many hydrogen atoms as possible, what is a monounsaturated fat? Look at the second molecule in the picture and you'll see a single double-bond between two carbon atoms. Because these two carbon atoms could each hold one more hydrogen atom if the double-bond were broken, it is unsaturated, and because it is only unsaturated at a single point, it is mono-unsaturated.
So then if a saturated fat is holding as many hydrogen atoms as possible, what is a monounsaturated fat? Look at the second molecule in the picture and you'll see a single double-bond between two carbon atoms. Because these two carbon atoms could each hold one more hydrogen atom if the double-bond were broken, it is unsaturated, and because it is only unsaturated at a single point, it is mono-unsaturated.
Polyunsaturated Fat
I guess you've figured out what polyunsaturated means now huh? Poly-, meaning two or more, means that a polyunsaturated fat (the third molecule) has at least two double-bonds between carbon atoms and potentially more. The most commonly known polyunsaturated fats today are the omega-3s and omega-6s. The 3 and 6 refer to a specific location of the first double-bond. I won't get into because I can sense your eyes glazing already and it's relatively unimportant.
I guess you've figured out what polyunsaturated means now huh? Poly-, meaning two or more, means that a polyunsaturated fat (the third molecule) has at least two double-bonds between carbon atoms and potentially more. The most commonly known polyunsaturated fats today are the omega-3s and omega-6s. The 3 and 6 refer to a specific location of the first double-bond. I won't get into because I can sense your eyes glazing already and it's relatively unimportant.
Trans Fat
Trans fats are the only of the four types of fat that are man-made. Through the process of hydrogenation, hydrogen atoms are added to (typically) polyunsaturated vegetable oils with the help of a nickel catalyst. Contrary to popular belief, high temperature frying and reusing oil does not produce trans fats. These fats canonly be produced when nickel is added and hydrogen is forced through an oil at high pressure.
Trans fats are the only of the four types of fat that are man-made. Through the process of hydrogenation, hydrogen atoms are added to (typically) polyunsaturated vegetable oils with the help of a nickel catalyst. Contrary to popular belief, high temperature frying and reusing oil does not produce trans fats. These fats canonly be produced when nickel is added and hydrogen is forced through an oil at high pressure.
Where Do I Find These Fats?
When talking about fats, it's important to realize that no fat source is purely saturated or unsaturated. For instance, pork lard is saturated, right? Well, sorta. For illustrative purposes, let's look at the fatty acids in pork lard: 41% is saturated, 47% is monounsaturated, and 11% is polyunsaturated. Olive oil is 75% mono-, 14% saturated, and 11% poly-. As you can see, these oils aren't purely one thing or another, but are a mix of various fatty acids.
Moving along, I'm going to paint with a very broad brush here. Foods like nuts and avocados are predominantly monounsaturated fat sources, as are olive and canola oils. Polyunsaturated fats are found in vegetable oils like corn, soy, and sunflower, along with in fish and fish oil. Animal products, including dairy, and the foods made from coconut (coconut cream, coconut milk, coconut oil) or palm oil are the main sources of saturated fat in the diet.
So Which Fats Should I Use?
Easy question, right? Mainly monounsaturated and polyunsaturated fats, keeping saturated fats to less than 10% of total calories, right? Hmm…maybe not. I go the "natural" route when it comes to choosing fats. That automatically knocks transfats out of the equation. They are man-made unnatural fats and are not good for you in any way, shape, or form.*
What else does my choice of natural fats rule out? Vegetable oils. Okay, so I just lost half of you who have now chalked me up to a quack. To the rest of you, here's the logic:
- Vegetable oils come from…vegetables (or grains in the case of corn)
- Vegetables and grains have very little fat
- Therefore, it takes HUGE quantities of these foods to make a little bit of oil, quantities far larger than any human could ever eat
- The extraction methods are suspect and involve such lovely terms as hexane and supercritical carbon dioxide (in comparison, olive oil is extracted by pressing olives)
- Further processing is necessary to remove impurities and most of the vitamins to enhance shelf-stability
- Polyunsaturated oils have been shown to suppress the immune system (and are used in organ transplants for this purpose)
Okay, so monounsaturated and saturated fats? Yep! These fats are readily available in nature and are the foods that have been consumed by humans for hundreds of thousands of years. Polyunsaturated vegetable oils are a 20th century creation. There is no evidence supporting the damnation of saturated fats. While polyunsaturated fats are not shelf-stable and need heavy refining, saturated fats are nearly impervious to oxidation and rancidity, owing to their high degree of saturation. They don't need to be refined and are rich sources of vitamins. It also means these are the proper fats for cooking, as poly- and monounsaturated fats tend to oxidize and spit free radicals throughout your body with application of heat and light.
It's unlikely anyone will argue with me about monounsaturated fats given their exalted status as a media darling due to the so-called Mediterranean Diet, so I won't waste your time making you read a treatise on why you should eat them.
To finish this long, winding explanation of the fats I recommend, here's a list: coconut oil, red palm oil, pork lard (from pastured pigs), real butter (NOT MARGARINE!) and olive oil. I do my cooking in the first four (though don't use butter much, for no real rhyme or reason) and add the last to vegetables and salads.
One Final Thing
This is just a brush of the surface when it comes to fats. In reality, the three broad categories of natural fats (I'm leavingtrans out of the discussion) are just that: categories. All monounsaturated fats aren't the same, nor are all saturated or polyunsaturated fats the same. As you delve deeper, which we aren't going to do today, you get into names like palmitic acid, butyric acid, lauric acid, etc.
I say this to point out the underlying reality of fats: it's far too complex of an area to be condensed to a single talking point of "fat is bad" or "fat is good".
What are your thoughts on the issue of fat? More is better? Less is better? Any other questions about fat? (I could talk for days.)
* Okay, there are small amounts of naturally-occurring trans fats that appear to have health benefits in a few foods…those aren't what is measured on the Nutrition Information panel and are inconsequential to our discussion.
