Cooking With Fats and Oils
Written by George Economou
We recently hosted our first Nutrition 201 seminar. The purpose of our 101 and 201 seminars is to educate our community and provide a baseline of information regarding digestive processes, foods and their macronutrient characteristics, effects of different foods on digestion, energy levels, and sports performance, and a host of other things. There was a question that came up at 201 that has popped up a few times in the past couple of months, “What are the best cooking fats?” That’s actually a really hard question! If you ask me what the best vegetables to eat are, my answer is pretty simple: buy organic, whatever is currently in season and locally produced, and include lots of variety. What’s the best meat to eat: free range, grass-fed, locally produced, lots of variety.
When it comes to fats, it’s hard to keep it too simple. You need to have a basic understanding of a few terms:
Lipids – fats and oils. If it’s solid at room temperature, it’s a fat. If it’s liquid at room temperature, it’s oil. Lipids are a collection of molecules called triglycerides.
Triglycerides – a molecule comprised of three fatty acids attached to a glycerol.
Fatty Acid – carboxylic acids (COOH for you chemistry junkies) with carbon chains running 2-24 carbons long. The most abundant fatty acids in food are 16-18 carbons long.
Saturated Fatty Acid – a fatty acid in which all the links between carbons on the chain are single bonds, leaving no free electrons to potentially share with something else. This is the most stable form of a fatty acid and is generally solid at room temperature.
Unsaturated Fatty Acid – fatty acids with one or more double bond between carbons. If there is only one double bond, it is a monounsaturated fatty acid; two or more and it is a polyunsaturated fatty acids. The fatty acids in the families of omega-3, omega-6, omega-7, and omega-9 fall into this category. These are not as stable as saturated fatty acids, which is why they are liquids at room temperature.
Trans Fatty Acid – an unsaturated fatty acid that has undergone the process of hydrogenation or partial hydrogenation. The fatty acid is bombarded with hydrogen atoms until those double bonds are broken up and the resulting free electron is shared with a hydrogen. These are really weird fats that look saturated, but the body generally doesn’t know how to work with them. There are some naturally occurring trans fats in ruminant animal fats, but these are different than the redheaded stepchildren coming from the hydrogenation process.
Melting Point– the temperature at which a lipid goes from solid to liquid.
Smoke Point – the temperature at which a lipid begins to break down to glycerol and free fatty acids. This is a bad place for fats as they can potentially turn into very toxic substances from here.
Ok, so now back to the question…”What are the best cooking fats?”
All food sources of fat are actually a combination of saturated, monounsaturated and polyunsaturated fatty acids, with one of those subcategories being the dominant type. For example, here is a breakdown by fatty acid type of some common cooking fats (unhydrogenated)[i]:
When picking a fat or oil for cooking, you want to choose it based on a few considerations: temperature you’re cooking at, fatty acid composition, and taste (my favorite).
The temperature plays a role because the fat shouldn’t be pushed to perform beyond its smoke point. My general rule of thumb is that if I’m cooking at a higher heat, I want to use a more saturated fat like coconut oil or ghee (clarified butter). Yes, I cook with butter…occasionally. After researching this topic, I’m going to try and get my hands on some beef tallow. When lightly sautéing something (knob on the stove is in the middle), I’ll use olive oil, avocado oil, or even sesame oil (sesame oil has really good oxidative stability, possible because its high content of sesamin – an antioxidant). When dressing a salad, I usually stick with olive oil, and we occasionally pick up a specialty oil like walnut or hazelnut. Here’s a link to a table of smoke points for various fats and oils: http://www.clovegarden.com/ingred/oilchart.html. There was a better one that I found at www.ISEO.org (Institute of Shortening and Edible Oils), but their website has been having some technical difficulties.
As for fatty acid composition, the body needs all types of fatty acids (except trans fats) in order to function optimally. There’s no one-size-fits-all formula, but generally 2-3% of caloric intake should come from omega-6 fatty acids, and 1-1.5% should come from omega-3 fatty acids (trying to achieve a balance of 2:1 or 3:1 omega-6:omega-3). The rest of your dietary fat is going to be a combination of saturated and monounsaturated fatty acids, and the majority should be saturated fat. This makes sense if you look at the human milk fat breakdown above. A key here is that if your diet is varied and you are eating whole, real food, you should be getting a pretty good balance of fats. If you’re eating mostly food by-products, you’re likely getting way more polyunsaturated fats.
My favorite consideration is taste! There’s just something about the rich flavor of butter (or my preferred clarified butter, ghee) that is hard to beat. Coconut oil and cocoa butter also leave their mark with soft, sweet hint of their fruits. I also love the taste of olive oil, and find that if I cook at too high a heat with it, the flavor goes away. If you’re feeling extra bold, try a mix of 1/3 coconut oil, 1/3 extra virgin olive oil, and 1/3 sesame oil. The coconut oil will have to be brought its melting point first, but it should easily mix with the other oils from there.
Something I found really interesting while researching this blog post was some data from the US Department of Agriculture and the Commerce Department. It was a comparison of the source of fats and oils in the United States 1890 vs 1990[ii]:
It’s pretty interesting to see such a drastic shift from saturated fats to unsaturated fats, and makes it hard to imagine that the shift hasn’t played a role in the current health crisis.
[i] M.G Enig. Know Your Fats: the complete primer for understanding the nutrition of fats, oils, and cholesterol. Bethesda Press, 2000. Pg 294
[ii] Enig. 90.