Choosing the Best Oils to Cook With and Which to Avoid

According to the American Heart Association, replacing bad fats with good ones is a smart choice for heart health. To make this informed switch, you must understand what are the best oils to cook with for different applications, as well as which ones should be avoided.

Quick Summary

An in-depth guide to selecting the right cooking oils based on their fatty acid profile and smoke point. The article covers healthy options like olive and avocado oil, explains why certain processed seed oils and trans fats should be avoided, and offers tips for different cooking techniques.

Key Points

• Match Oil to Temperature: The right oil for the job depends on its smoke point; high-heat cooking requires stable fats like refined avocado or olive oil.

• Refined vs. Unrefined: Refined oils are stripped of solids for higher smoke points, while unrefined oils (like EVOO) retain more nutrients and flavor but are best for low-heat or no-heat use.

• Avoid Unstable Polyunsaturated Fats: Many common seed oils like soybean, corn, and sunflower (high-linoleic) are unstable at high temperatures and can produce harmful compounds.

• Limit Saturated Fats: While stable for cooking, saturated fats like coconut oil should be consumed in moderation due to their impact on LDL cholesterol levels.

• Never Reuse Fried Oil: Reheating oil, especially less stable polyunsaturated fats, drastically increases the concentration of damaging free radicals.

• Prioritize Unsaturated Fats: The American Heart Association recommends replacing saturated and trans fats with healthier monounsaturated and polyunsaturated fats.

• Store Oil Properly: Keep oils away from heat, air, and light to prevent them from going rancid, which can ruin flavor and nutritional value.

Understanding the Science of Cooking Oils

Choosing the right cooking oil goes beyond taste preferences; it's about understanding how different oils react to heat and what happens to their chemical structure during cooking. All fats are made of fatty acids, but their saturation levels determine their stability. Saturated fats have a stable, single-bonded structure and are solid at room temperature, while unsaturated fats (monounsaturated and polyunsaturated) have one or more double bonds and are typically liquid.

When an oil is heated past its smoke point, it begins to break down and oxidize, releasing free radicals and other harmful compounds. This not only imparts a burnt flavor to food but can also contribute to cellular damage over time. This is why matching the oil to the cooking method is critical for both flavor and health.

Best Oils for High-Heat Cooking

For high-heat applications like frying, searing, or roasting, you need oils with a high smoke point and a stable fatty acid profile. Saturated fats and some monounsaturated fats are ideal because their bonds don't easily break down when heated.

• Refined Avocado Oil: With a very high smoke point of 480-520°F, this oil is extremely versatile and suitable for almost any high-heat cooking. It is high in healthy monounsaturated fats and has a mild flavor.
• Light or Refined Olive Oil: While extra virgin olive oil has a lower smoke point, light or refined olive oil is suitable for higher temperatures. The refining process removes solids, making it more stable for frying, while still containing heart-healthy fats.
• Peanut Oil: This oil has a high smoke point (450°F) and a mild flavor that won't overpower your food, making it a staple for Asian cuisine and stir-frying.
• Ghee (Clarified Butter): As a saturated fat, ghee is very stable under high heat (around 400°F). It is rich and flavorful, but should be used in moderation.

Best Oils for Low-Heat and No-Heat Applications

Some oils contain delicate, beneficial compounds that are destroyed by high heat. These are best used for dressings, marinades, or drizzling over finished dishes.

• Extra Virgin Olive Oil (EVOO): The unrefined nature of EVOO provides a richer flavor and higher antioxidant content than its refined counterpart. It is perfect for salad dressings, sauces, or drizzling, but its smoke point is too low for high-heat cooking.
• Flaxseed Oil: This oil is a fantastic source of omega-3 fatty acids but has an extremely low smoke point (225°F). It should never be heated and is best used in cold dishes, smoothies, or as a supplement.
• Walnut Oil: With a rich, nutty flavor, walnut oil is best used as a finishing oil. It has a low smoke point and is not suitable for cooking.

Which Oils to Avoid for Cooking

Several oils, particularly highly processed seed oils and those high in certain fatty acids, can be problematic when heated. The issue often lies in their instability and the chemical processes used to refine them, which can strip away beneficial nutrients and leave harmful residues.

• Soybean Oil: A common polyunsaturated fat used widely in packaged foods. When heated, its high omega-6 content can promote inflammation.
• Corn Oil: Similar to soybean oil, corn oil is a polyunsaturated fat that can become unstable and produce harmful compounds when heated to high temperatures.
• Sunflower and Safflower Oil (high-linoleic): These oils are high in polyunsaturated fats and can produce toxic aldehydes when cooked at high heat. High-oleic versions are more stable.
• Partially Hydrogenated Oils: These are created by adding hydrogen to liquid vegetable oil to make it more solid and shelf-stable. The process creates trans fats, which are widely recognized as detrimental to heart health and should be avoided entirely.

Comparison Table: Popular Cooking Oils

Oil	Best For	Smoke Point (°F)	Fat Profile	Notes
Refined Avocado Oil	High-heat frying, searing	480-520	High monounsaturated fat	Very versatile, mild flavor.
Refined Olive Oil	High-heat cooking, frying	390-470	High monounsaturated fat	More stable than EVOO for heat.
Extra Virgin Olive Oil	Low-heat cooking, dressings	320-375	High monounsaturated fat	Rich flavor, not for high heat.
Peanut Oil	Frying, stir-frying	450	High monounsaturated fat	Mild flavor, great for Asian dishes.
Ghee	High-heat cooking	375-400	High saturated fat	Rich, buttery flavor, use in moderation.
Coconut Oil (Refined)	Moderate-heat sautéing	400	Very high saturated fat	Distinctive flavor, controversial health profile.
Canola Oil	High-heat cooking, frying	400-475	High monounsaturated fat	Versatile, but highly processed.
Flaxseed Oil	No-heat uses only	225	High polyunsaturated fat	Rich in omega-3s, sensitive to heat.

Conclusion: Making the Right Choice for Your Health

Selecting the best oils to cook with is about knowing their properties and matching them to your cooking needs. For high-heat methods, refined oils like avocado and light olive oil are safe and stable choices. For dressings and low-heat applications, extra virgin olive oil and flaxseed oil offer superior nutritional benefits and flavor. Avoiding highly processed seed oils and trans fats, especially when cooked at high temperatures, is a crucial step toward healthier eating.

While personal taste is a factor, prioritizing the health and stability of your cooking oils is a simple but impactful way to improve your overall wellness. By keeping a few different, high-quality oils in your pantry for specific uses, you can ensure your meals are both delicious and healthy. For more detailed information on healthy fats, consider consulting reputable health organizations such as the American Heart Association.

The Role of Monounsaturated vs. Polyunsaturated Fats

Understanding the difference between monounsaturated and polyunsaturated fats is key to selecting the right oil. Monounsaturated fats, like those found in olive and avocado oil, have one double bond and are quite stable. Polyunsaturated fats, found in many seed oils like sunflower and soybean, have multiple double bonds, making them more susceptible to oxidation and degradation when heated. This is why even a moderate temperature can be detrimental to polyunsaturated oils, making them less suitable for frying.

The Hidden Dangers of Reusing Cooking Oil

Reusing cooking oil, especially for deep frying, significantly increases the concentration of harmful free radicals and toxic compounds. Restaurants often reuse the same oil multiple times, particularly low-stability polyunsaturated fats, creating a health risk. For home cooks, it's best to avoid reheating and reusing oil, and if you must, use a stable oil like refined olive or avocado and dispose of it after one or two uses.

Best Practices for Storing Cooking Oils

Proper storage is essential to maintain the quality and shelf life of your cooking oils. Exposure to heat, air, and light can accelerate oxidation and turn oil rancid. Always store oils in a cool, dark place, and for delicate oils like flaxseed and walnut, consider refrigerating them to extend their freshness. A rancid oil will not only taste bitter but will have lost most of its health benefits.

The Myth of Coconut Oil

Coconut oil, a popular but controversial choice, is very high in saturated fat. While its saturated fat content makes it stable for moderate heat cooking, evidence shows it can significantly increase LDL ('bad') cholesterol compared to other vegetable oils. For heart health, health professionals generally recommend limiting its intake and prioritizing oils high in unsaturated fats.

Lists

Best oils for high-heat cooking:

• Refined Avocado Oil
• Light or Refined Olive Oil
• Peanut Oil
• Refined Canola Oil
• Ghee

Best oils for low-heat and no-heat uses:

• Extra Virgin Olive Oil
• Flaxseed Oil
• Walnut Oil
• Unrefined Avocado Oil
• Sesame Oil

Oils to limit or avoid for cooking:

• Soybean Oil
• Corn Oil
• Sunflower Oil (high-linoleic)
• Safflower Oil (high-linoleic)
• Partially Hydrogenated Oils (contains trans fats)

Conclusion

Understanding the nuanced world of cooking oils is crucial for making informed choices that support long-term health. The selection of an oil should depend on its intended use, with stable fats being reserved for high-heat cooking and more delicate, nutrient-rich oils for lower-temperature applications. By prioritizing unsaturated fats from sources like olives and avocados while minimizing intake of highly processed seed oils and trans fats, you can build a more heart-healthy kitchen. Being mindful of an oil's smoke point and proper storage ensures that you are maximizing both its health benefits and flavor profile. A smart pantry contains a variety of oils, each chosen for its unique properties and culinary purpose.

American Heart Association - Healthy Cooking Oils

Frequently Asked Questions

What is the best all-purpose oil for cooking?

For an all-purpose oil, refined avocado oil is an excellent choice due to its very high smoke point and mild flavor, making it suitable for a wide range of cooking methods.

Why is extra virgin olive oil not ideal for frying?

Extra virgin olive oil (EVOO) is unrefined, meaning it contains solids that will burn and release harmful compounds when exposed to high heat. It has a lower smoke point and is best used for dressings or low-heat sautéing.

Are all saturated fats bad for you?

While saturated fats like coconut oil and ghee are stable for high-heat cooking, they should be consumed in moderation. High intake has been linked to increased LDL ('bad') cholesterol, and unsaturated fats are generally considered healthier.

Why should I avoid partially hydrogenated oils?

Partially hydrogenated oils contain trans fats, which are created through a chemical process. Trans fats are known to increase LDL cholesterol and the risk of heart disease and should be avoided completely.

What happens if oil smokes while I am cooking?

When oil begins to smoke, it has reached its smoke point and is breaking down. It releases free radicals and toxic compounds that can be harmful to your health and will also give your food a burnt, unpleasant flavor.

Is canola oil bad for you?

Canola oil is a highly processed vegetable oil that has sparked debate. While it has a high monounsaturated fat content, it's often refined using chemical solvents and should be used with caution, especially when repeatedly heated.

How should I store different cooking oils?

Most cooking oils should be stored in a cool, dark place away from heat and light to prevent them from oxidizing and turning rancid. Delicate oils like flaxseed should be refrigerated to extend their shelf life.