Sometimes nutrition research can give you a bit of whiplash. First fat was bad for you. Then it became good again. Sometimes eggs are evil, and at others, you want to have as much PUFAs (poly-unsaturated fatty acids) as possible.
The terminology is confusing, and it detracts from the most important part: what the heck you should actually consume in your diet.
In today’s post, we’ll show you the differences between saturated, unsaturated and trans fats. But we’ll go beyond the chemistry and show how these different compounds actually affect your body. I’ll share which oils I use in my kitchen, and when it’s most appropriate to use them (because some fats are better than others for cooking). There’s a lot of amazing information here, and you’ll definitely pick up great tips and new ingredients to be using in your kitchen.
Are you ready? Let’s go!
When we eat fat…what is it? The most common fat we consume is called a triglyceride. There are actually many different triglycerides that have a similar (but not exact) chemical structure.
All triglycerides have a glycerol molecule and 3 fatty acid chains. These chains can be saturated, monounsaturated, or polyunsaturated.
Saturated means that the chemical structure looks like this:
The ball represents the glycerol, and you can see three squiggly lines, which represent the fatty acid chains. Fatty acids are actually chains of carbon atoms all linked together.
In a saturated fat, these carbons are all held together by single bonds, so the three chains lie close together.
A monounsaturated fat, on the other hand, looks like this:
There is a double bond between two of the carbons, in the chain, which creates a little “kink”, and the fatty acid chain goes in the other direction. This kink means that the fats can’t be packed together as closely as they can with a saturated fat.
You can also have a polyunsaturated fat:
Polyunsaturated which means that there are multiple double bonds between carbons, so you have more kinks in the carbon chain, and the fat takes up even more space!
What’s the difference between saturated, monounsaturated, and polyunsaturated fats?
When you have saturated fat, you can pack things together a lot closer. Once you start adding all these kinks (the unsaturated part), the fats don’t fit together as tightly so the resulting fat is a lot more fluid. A good example of this is olive oil. Olive oil is mostly monounsaturated fat, and it’s liquid at room temperature.
A fat like butter, lard, or coconut oil, are a lot more saturated fats. Because these fats can pack together more tightly, they are solid at room temperature. So solid vs liquid fats are all about how saturated the oil is, and how tightly the fatty acid chains are packed together.
In our bodies, these saturated fats are potentially not healthy for us because they make our blood vessels more stiff. This isn’t good when your heart is pumping hard, or if you have high blood pressure due to hypertension.
How does saturation affect cooking?
The other things that happen when you move things from a totally saturated fat to a polyunsaturated fat is that the fats become less stable.
The kinks (or points of unsaturation) are hard to keep intact. So saturated fats are more stable than unsaturated fats. What this means in practice is that if you heat up a polyunsaturated fat, it’s going to start to degrade a lot faster than a saturated fat. This process is called oxidation, and we often call it “going rancid.”
The same thing can happen at room temperature (though it happens at a much slower rate). Polyunsaturated fats when exposed to a high temperature or light starts to oxidize.
This is why oils like flax oil need to come in a dark bottle and are stored in the refrigerated section of the grocery store. Flax oil is super high in polyunsaturated fatty acids, and the low temperature and dark bottle help protect the oil.
We can keep olive oil at room temperature, but storing in a closet or a dark bottle will definitely help it stay better for longer.
If you try to cook with an oil high in mono or polyunsaturated fats, you’ll notice that it starts to smoke at a low temperature, and may even start to smell bad. This is oxidation, and it’s definitely not healthy for you to eat that oil!
If you’re cooking at a high heat, you want to use a more saturated oil, or an oil that has a higher smoke point.
Medium Chained Triglycerides (or why people are in love with Bulletproof Coffee)
Medium chained triglycerides (or MCTs) refers to the number of carbons in the fatty acid chain. Most of the fatty acids we eat are considered long-chained fatty acids, like the one shown below.
A medium chain fatty acid, on the other hand, as a lot less carbons in that fatty acid chain.
We find a lot of MCTs in fats like coconut oil.
What’s cool about these MCTs is that because they’re so much smaller, we absorb them differently than long chain fatty acids.
To get a long chain fatty acid in from your small intestine to your bloodstream takes a lot of work. We need to package them into a chylomicron, carry them into our lymphatic system, and then have them circulate up to our heart before they enter the blood stream.
MCTs are much smaller, and we’re able to pull them directly into our blood stream (bypassing the packaging and carrying in the lymph). As a result, we can use them faster for energy!
That’s why in my Banana Coconut recovery muffins, which are specifically formulated for our post-workout snack, I include coconut in many forms (read more about these fabulous muffins, and download the recipe here!)
Why are trans fats so bad for you?
I want to talk about trans fats and partially hydrogenated fats. Trans fats show up all the time in many food products, but they’re also shown to be associated with cardiovascular disease and Alzheimer’s.
So here’s what a trans fat looks like:
He doesn’t look that happy. That fatty acid kinks in towards the center instead of kinking out to the side like the unsaturated fatty acids. When we hydrogenate, the carbon chain forms a shape that is hardly ever found in nature.
When we have a lot of trans fats in our body, our body can’t process them efficiently and effectively, and disease results. This is another reason why we want to stay away from oils that are oxidized at high heat – this oxidation can cause some trans fats to form, turning our super healthy olive oil into a much less healthy oil.
Let’s talk about processing, because some oils are much more processed than others. This processing affects how healthy certain oils are for you.
Cold-Pressed or Pressed Oils
For cold-pressed oils (typically we see olive oil made this way), the olives are squeezed so that the oil comes out of them. Kind of like you’re squeezing an orange for orange juice. Simple.
Expeller-pressed oils are very similar to cold-pressing oils, except that there is potential for the oil to heat up due to friction.
Refined oils like canola or sunflower oil have much more processing involved than the pressed oils.
With a refined oil, they press out the oil, but then they also use a chemical solvent and apply pressure to help get more oil out of the nut, seed, or grain. Using a combination of heat, pressure, chemicals, and deodorizers, the processers are able to get a higher yield of oil from the product.
This, as you can imagine, is not very healthy for you. Chemical additives aside, the pressure and heat can act to oxidize the oils – turning your beautiful unsaturated fats into dangerous, inflammation-causing compounds.
Which do you choose?
Always go for cold-pressed or expeller-pressed oils. That ensures that chemical additives haven’t been added, and that the oils have been kept at a lower heat. Ultimately, that means a more stable, healthy product.
But I thought canola oil was so healthy for me?
We’ve been told for years that canola oil is a healthy oil, because it’s incredibly high in unsaturated fats. However, all canola oil is also refined, and the process needed to make the canola oil involves all of the pressure, heat, and chemical solvents I discussed above. Plus, canola oil is high in omega-6 fatty acids, fatty acids that act to increase inflammation in our bodies. To see the process for yourself, click here.
A word about oil quality
Unfortunately, many of the oils we come across are not as high quality as they seem. Research studies have found that many “olive oils” are actually a mix of olive and cheaper refined oils (See this eye-opening report from UC Davis).
If you want to know that your olive oil is pure, high quality, you’ll do better to consume domestic (US-based olive oils), or to buy olive oils that are produced by a single farmer or small co-op.
Palm oil has been showing up more and more often as food manufacturers try to remove trans fats from their products. Palm oil is higher in saturated fat, and appears to be healthy for you.
However, there are many environmental concerns related to palm oil production. The high demand for palm oil has led to a lot of deforestation and rain forest destruction. So, if you’re buying palm oil (or consuming products with palm oil), look for a CSPO certification. This certification lets you know that it’s been sustainably harvested. You can learn more about the CSPO certification and which brands make the cut here.
My favorite oils and fats.
I want to close with my favorite fats and oils I use for in my kitchen.
Flax Oil: Flax oil is a fabulous oil for raw salads, cold porridges, and drizzling on top of vegetables. Flax oil is high in beneficial omega-3 fatty acids, which helps to lower inflammation, boost your immune system, and give you better skin.
Best of all, flax oil tends to be very carefully made and packaged, because it’s very sensitive to light or heat. Look for it in the refrigerated section!
Olive Oil: I use cold-pressed, extra virgin olive oil for most of my salads and cooking. You can use it in soups and for sautéing, but if the oil starts to smoke, turn the heat down!
Coconut Oil: I use unrefined coconut oil in baked goods as well as dishes where I want a slight tropical flavor. It’s great for fast energy after workouts, which is why I use it in my banana coconut recovery muffins.
Avocado Oil: I keep avocado oil around if I want to cook my food at a higher heat. This is the oil to use when you’re frying because it stays stable at a higher temperature. I like La Tourangelle.
While fats are undeniably good for us, there is a school of thinking that too many oils in our diet are not beneficial.
The reason is because all oils are a processed product, and in consuming them, we’re stripping away fiber and other beneficial nutrients we would be getting if we at a whole olive, or a coconut, or an avocado. All oils, by being stripped from these other nutrients, are going to be less stable and more prone to oxidation than the foods they came from.
So the best way to get fat in your diet is not by slathering oil on everything you make, but eating whole foods that are high in fat. Toss some seeds, avocado, eggs, and olives into your dishes to get the fat you need, in addition to many beneficial nutrients.
Let’s hear from you
What oils do you use in the kitchen? Has this article changed any of the ways you buy and use oils? Leave your answers in the comments below.
Thanks for reading, and have a wonderful day,
Samantha Attard, PhD, is the founder of Happy Healthy Human. Sam is a performance coach and yoga instructor who helps people eat, move, and live with intention. Learn more here.