A Dietitian's Guide To Cooking Oils

Updated: Aug 3, 2021



As a dietitian, I'm often asked which oils are best for cooking, baking, "bullet-proof coffee" making, and every endeavor in between. And as a whole-foods plant-based nutritionist, the debate of whether oils are even healthy in the first place always finds it's way to my desk.

So today, I'm giving it to you straight. We're diving into the most common plant-based oils, the productions methods, smoke points, and nutrient profile of each, as well as how to select, store and cook safely with those that suit your family's interests.


Whether you're looking for the perfect frying oil for your homemade plantain chips, in active recovery from a major cardiac episode, or simply seeking evidence-based information on this confusing and often contradictory topic, let's cut through the fat and get to the facts here.



1. Olive Oil


Traditionally, olive oil was the liquid fat extracted in the process of crushing fresh olives into a paste. Today, however, most olive oils are extracted using chemical solvents (resulting in "refined" olive oil), or through the process of centrifuging crushed olives at high speeds in order to separate the oil from the other components of the fruit. This chemical-free centrifuge method is how "virgin" and "extra-virgin" varieties are attained. And while these titles seem fancy and concrete, they are actually designations provided based upon chemical standards and the sensory experiences of trained testers. Extra-virgin olive oil, for example, is typically darker green in hue, and offers a peppery, fruity flavor and aroma in comparison to its alternative.


The label "cold-pressed" has an even less ground to stand on, in terms of its connotation with a higher quality product, as nearly all modern day producers of olive oil use the centrifuge method over pressing, and all virgin and extra-virgin varieties are made without heat.



Speaking of heat, olive oil has smoke point between 350-410 degrees F. This means it will start to burn and release harmful compounds within that temperature window, with exact smoke points depending on the quality of the individual product.


Product quality also matters in terms of the health effects associated with olive oil. A large study from the New England Journal of Medicine, for example, found that moderate amounts of polyphenol-rich olive oil were associated with a 30% reduced risk of heart attack, stroke, and dying of cardiovascular disease in comparison with the control group eating a similar, but lower-fat diet. Virgin and extra-virgin varieties are known to have more of these powerful antioxidant polyphenols than their refined alternatives, as they are less processed and naturally rich in Vitamin E.


When it comes to cooking, olive oil is fantastic for dressings, marinades, roasting, sautéing, and even suitable for frying due to its high smoke point and stability (thanks to all those disease-fighting antioxidants). I personally use olive oil to add flavor and mouthfeel to Italian classics (like My Favorite Vegan Lasagna recipe), or pairing earthier varieties of the stuff with vinegar and/or creamy hummus for dairy-free salad dressings.


2. Coconut Oil


If there's any food that's sure to stir the pot of controversary at an extended family gathering these days, it's coconut oil.


Coconut oil is made by extracting the liquid fat from coconut meat, with refined varieties coming from dried coconut solids, and virgin coconut oil from fresh coconuts. Due to the variations in quality and processing method, the smoke point of coconut oil varies quite a bit. Virgin coconut oil can be heated up to about 350 degrees F, while refined coconut oil remains stable up to 400 degrees F or so.


And while this creamy fat makes for delicious baked goods and is one of my all-time favorite skin moisturizers (hello tropics!), it's value from a nutrition perspective fails to impress. With 11-13 grams of saturated fat (one of the key contributing risk factors for metabolic syndrome, insulin resistance and cardiovascular disease) per measly tablespoon, I certainly wouldn't call the stuff "healthy" in any traditional sense of the term. With so much research connecting saturated fat intake to increased LDL cholesterol, heart disease and stroke incidence, it's no wonder why the American Heart Association recommends we limit saturated fat intake to no more than 13 grams daily. That's ONE tablespoon of food, knocking out ALL your saturated fat tokens for the entire day. Sorry coconut oil, I'm going to need my "delicious budget" to take me a little further.



Though it's well-known that coconut oil is high in saturated fat (similar to butter, lard, beef-fat, palm oil, cheese or cream) - it's fiercely loyal keto supporters look past this shortcoming to instead tout it for it's medium-chain triglyceride (MCT) content. Unlike longer-chain fatty acids, MCTs go straight to the liver where they can be used as an instant energy source, making them less likely to be stored as fat. There's just one problem. The main MCT in coconut oil is lauric acid, which behaves differently than other medium-chain fatty acids. Unlike, capric, caprylic, or caproic acid, lauric acid is digested more slowly, similar to long-chain fatty acids. For this reason, it is debated whether or not the potential (and scarcely supported) benefits of MCTs even apply to coconut oil at all.


My take?


A serving of coconut oil in a brownie here or a homemade waffle there is nothing to be afraid of (especially if you are limiting other sources of saturated fat like dairy or beef). But would I guzzle a spoonful down in my morning coffee day in and day out? No. I think I'll stick with skin moisturizing as far as a daily coconut oil habit goes.


3. Canola Oil


Canola oil, also known as rapeseed oil, is the Game of Throne's of all oils in my book. Polarizing, charming from a distance, but ultimately too fake for my liking.

While canola is low in saturated fat, rich in the omega-3 fatty acid ALA, and has a relatively high smoke point of 400-450 degrees F, it certainly has its downsides as well. Most notably, canola oil is typically made from genetically-modified rapeseed plants, which some studies associate with uniquely high levels of pesticide residues. Not only that, but it is most often extracted using chemical solvents (like hexane), and then bleached, deodorized and highly refined prior to sale.


And though it's smoke-point would appear to make it a decent candidate for high-heat cooking, studies show it's quicker to oxidize and release harmful compounds than other oils like olive and coconut. So while it's tempting to use this neutral-tasting oil for frying and searing, it's actually better saved for low-heat baked goods and condiments.

It is worth mentioning, however, that organic, cold-pressed, non-GMO canola oils are available. However given these higher-quality varieties are harder to come by, I personally gravitate towards other oils for my home.



4. Avocado Oil


Next up, avocado oil.


Avocado oil is extracted from fresh avocado meat using either cold-press methods or chemical solvents like hexane. And while avocados are praise-worthy over their nutrient content alone, the real claim to fame for this product is its uniquely high smoke point. Avocado oil can be heated up to 520 degrees F and remains stable over high heat, making it a prime candidate for all cooking methods.


While avocado oil is fairly new to the market and more studies on its unique health benefits are needed, we do know it is low in saturated fat and high in monounsaturated fat. This means that when used in place of butter, lard, palm or coconut oils, consumers of this heart-healthy choice can expect a reduction in their LDL cholesterol and heart disease risk.

I personally love to use avocado oil for sautés, dressings and the occasional batch of fried plantains. With its neutral taste, unique stability and tolerance for high-heat cooking, this product is an absolute staple in my house.


5. Grapeseed Oil


And lastly, grapeseed oil.


As the name implies, grapeseed oil is extracted from the seeds of grapes, and has a relatively high smoke point of approximately 420-485 degrees F. Like many of the oils mentioned previously, grapeseed oil can be extracted using chemical solvents like hexane, or unrefined using cold or expeller-pressed methods. And though residual hexane levels in these commercial oils often fall well below designated safety limits, chemical extraction understandably raises concern for many shoppers.


Nutritionally speaking, grapeseed oil is low in saturated fat, rich in polyunsaturated fats and a good source of vitamin E, a fat-soluble vitamin and antioxidant. And while the omega-6 fatty acids in grapeseed oil are known to be beneficial when replacing saturated fat in the diet, it's important to mention that limiting omega-6 fatty acids, and increasing intake of omega-3 fatty acids (like those found in hemp, flax, chia, walnuts, algae-based EPA/DHA, etc.) is truly the quickest route to reducing inflammation and heart disease risk. However, with a national diet centered around highly-processed and refined snack foods, cold-pressed grapeseed oil isn't typically where most Americans overindulge in the omega-6 department.



In summary, with grapeseed oil and omega-6 rich fats in general, the goal is to focus on eating minimally-processed products, and aiming to infuse more omega-3 goodness into the diet to limit that omega-6 to omega-3 ratio.

Since many oils and highly-refined foods tend to be concentrated sources of omega-6 fatty acids, and many lesser refined foods tend to be rich in omega-3s, this poses the question: are oils even healthy in the first place?

Before I offend or confirm any one individual's philosophy here, let's start with what we know.


Dietary fat plays critical roles in the formation of neurotransmitters, hormones, and allowing the body to absorb fat-soluble vitamins such as vitamins A, D, E and K. It is necessary for temperature regulation, organ insulation, healthy hair, skin, and nails, and plays critical roles in our ability to learn and memorize complicated concepts as intellectual beings. Not to mention it is absolutely vital for healthy development in children, pregnant and lactating women, and also contributes to satiety by enhancing flavor, mouth-feel and slowing the process of digestion.


And while a few very small studies have shown reduced endothelial cell function immediately following oil consumption, these changes in vascular health only last a short period of time, leaving little evidence that oil is harmful in the long run. However, we do know that oil is the densest source of calories known to man (at 4,000 calories per pound), and completely devoid of other beneficial food components like fiber. This means that while eating a half an avocado on toast might provide you with enough fiber, protein, and potassium to satisfy your body's snack-time needs, a slice of toast topped with a few teaspoons of avocado oil likely won't get the job done.


All in all, I recommend getting your dietary fat from whole, plant foods as often as possible, while also knowing that oil can be a part of any healthy diet in moderation.



As with any processed product, a lot can become a problem, sure - but demonizing and avoiding every drop of oil altogether doesn't serve anyone's body, mind, or social life either. Like with most controversial nutrition topics, wellness lies somewhere in the middle. And when we stop looking to fitness gurus or celebrity "experts" for militant dietary advice, we are better able to tune into our bodies' needs, and honor those with common sense, flexibility and mental wellness in mind.


I hope you found this post to be a valuable, objective resource amongst the noise of marketing claims, biases and vested interests on this topic.


The majority of these cold-pressed oils can be found in top grocery chains or health-food markets (like Whole Foods, Sprouts, etc.) nationwide, if not deliverable via online retailers such as Amazon or Thrive Market.


For more personalized recommendations or further information on dietary fats and oils, please feel free to reach out privately. I would love to formulate a balanced approach to wellness with your specific preferences or dietary restrictions in mind.


Cheers & until next time!

Gracie

This post was written & medically reviewed by a Registered Dietitian Nutritionist.

Grace Pascale, MS, RDN. Grace Pascale Nutrition.

279 views0 comments