Which oils are best and worst for you?

December 25, 2025 •

5 min read

While all oils are rich in calories, not all are created equal in terms of nutritional value. Choosing the right cooking oils, based on their fat profile and stability, is crucial for promoting heart health and reducing inflammation. This guide explains which oils are best and worst for you, covering key factors like processing, smoke point, and fatty acid composition.

Quick Summary

This article explores the health impacts of different cooking oils, analyzing their fat content, processing, and heat stability. It details which oils, like extra virgin olive and avocado, are beneficial for health and which, including highly processed vegetable and seed oils, should be limited. It emphasizes making informed choices based on scientific evidence.

Key Points

Fatty Acid Profile: Monounsaturated and polyunsaturated fats are generally healthier than saturated fats, with the exception of coconut oil's medium-chain triglycerides.
Refinement Matters: Unrefined (cold-pressed) oils retain more nutrients but have lower smoke points, while refined oils are processed to have higher smoke points but lose beneficial compounds.
Best for High Heat: Refined avocado oil is a top choice for high-heat cooking due to its high smoke point and healthy monounsaturated fat content.
Best for No Heat: Flaxseed and walnut oils are rich in omega-3s but should only be used in cold dishes like dressings because they are unstable when heated.
Worst Offenders: Avoid partially hydrogenated oils containing trans fats entirely. Limit highly processed vegetable and seed oils that are high in omega-6s, especially when heated.
Read Labels: Look for 'cold-pressed' or 'unrefined' to ensure higher nutrient retention. Check for harvest dates and opt for dark glass bottles to protect oil quality.
Don't Fear All Fats: Fats are essential for nutrient absorption and overall health, but the type and moderation are key to a balanced diet.

Understanding the Fundamentals: Fat Types and Processing

When it comes to understanding which oils are best and worst for you, it's essential to look beyond the surface level of marketing. The healthfulness of an oil is largely determined by its fatty acid profile, degree of refinement, and stability under heat.

The Role of Fatty Acids

Oils are composed of different types of fatty acids, which behave differently in the body and when heated. The three main types are:

Saturated Fats: Found in high amounts in coconut oil, palm oil, and animal fats like butter and lard. These are solid at room temperature and have historically been linked to higher LDL ('bad') cholesterol levels, though recent research offers a more nuanced view, especially for sources like coconut oil.
Monounsaturated Fats (MUFAs): Present in extra virgin olive oil and avocado oil. These are liquid at room temperature and are known to promote heart health by helping to lower LDL cholesterol. They are also relatively stable when heated.
Polyunsaturated Fats (PUFAs): Abundant in seed oils like sunflower, corn, and soy. This category includes omega-3s (beneficial) and omega-6s (essential but can promote inflammation in excess). PUFAs are the least stable when heated, making some seed oils unsuitable for high-temperature cooking.

The Importance of Processing and Refinement

The method used to extract oil from its source has a significant impact on its nutritional quality. Unrefined, or cold-pressed, oils are extracted mechanically without high heat or chemicals. This preserves beneficial compounds like antioxidants and polyphenols but often results in a lower smoke point. Refined oils, conversely, undergo extensive processing using chemicals, heat, bleaching, and deodorizing to create a neutral-flavored, high-smoke-point oil. This process strips away many of the oil's natural nutrients.

The Best Oils for Your Health

Here are some of the most highly recommended oils for their health benefits, stability, and versatility.

Extra Virgin Olive Oil (EVOO): A cornerstone of the Mediterranean diet, EVOO is rich in monounsaturated fats and powerful antioxidants. It is suitable for low-to-medium heat cooking, baking, and for dressings. Its beneficial properties are well-supported by decades of research.
Avocado Oil: With a high smoke point and a high concentration of monounsaturated fats, avocado oil is an excellent choice for high-heat cooking methods like searing, roasting, and frying. It has a mild flavor and is also rich in vitamin E.
Macadamia Nut Oil: This oil has a rich, nutty flavor and is notably high in monounsaturated fats, similar to olive oil. It is also heat-stable and can be used for both cooking and dressings.
Flaxseed Oil: Extremely rich in the omega-3 fatty acid alpha-linolenic acid (ALA), flaxseed oil is best used for cold applications like salad dressings or drizzled over finished dishes. Its very low smoke point means it should never be heated.

The Worst and Most Controversial Oils

These oils are either high in saturated fats or prone to oxidation when heated, potentially forming harmful compounds.

Highly Refined Seed Oils: This category includes corn, soybean, and cottonseed oils. Often found in processed foods and commonly used for frying in restaurants, these oils are typically high in omega-6 fatty acids. The refining process strips nutrients, and when heated, they can become unstable.
Partially Hydrogenated Oils: These contain trans fats, which are widely recognized as harmful. They raise LDL ('bad') cholesterol and lower HDL ('good') cholesterol, significantly increasing the risk of heart disease.
Palm Oil: Although naturally stable, palm oil is high in saturated fat. Its production is also associated with significant environmental and ethical concerns related to deforestation.
Coconut Oil: This oil has a very high saturated fat content. While some studies point to benefits from its unique medium-chain triglycerides (MCTs), others confirm it raises LDL cholesterol more than unsaturated oils. It is best used sparingly.

Comparison of Common Cooking Oils

Choosing the right oil depends on its intended use, especially the heat level. The table below compares several popular oils based on key factors.


Oil Type	Primary Fat Type	Smoke Point	Best Use	Notes
Extra Virgin Olive Oil	Monounsaturated	Medium (325-400°F)	Dressings, low-to-medium heat sautéing	Rich in antioxidants, distinctive flavor.
Avocado Oil (Refined)	Monounsaturated	High (520°F)	High-heat searing, frying, roasting	Neutral flavor, very heat stable.
Coconut Oil (Refined)	Saturated	High (450°F)	High-heat sautéing, stir-frying	High in saturated fat, use sparingly.
Canola Oil	Mono/Polyunsaturated	High (400°F)	Baking, sautéing, grilling	Often highly refined, low saturated fat.
Vegetable Oil Blend	Polyunsaturated	Medium-to-High (400°F)	All-purpose, deep frying	Typically a mix of high-omega-6 seed oils.
Flaxseed Oil	Polyunsaturated (Omega-3)	Very Low (225°F)	Dressings, cold finishing	Must not be heated; rich in omega-3.

How to Choose the Right Oil for Your Kitchen

Making informed choices about oil consumption involves considering several factors beyond just "healthy" or "unhealthy." A healthy diet incorporates a variety of minimally processed whole foods, including various sources of beneficial fats.

Prioritize Unrefined Oils for Flavor and Nutrients

For low-heat cooking, dressings, and dips, prioritize unrefined options like extra virgin olive oil. Their nutrient profiles are superior, and they offer richer, more complex flavors. Storing them in a cool, dark place is crucial to prevent oxidation.

Use Heat-Stable Oils for High-Temperature Cooking

When searing, frying, or roasting at high temperatures, choose oils with a high smoke point and good thermal stability, such as refined avocado oil. Some saturated fats like ghee and coconut oil are also heat-stable, but their higher saturated fat content means they should be used in moderation.

Limit Processed Seed Oils and Trans Fats

Reducing the intake of highly refined vegetable oils found in many processed and fast foods is a sensible approach. The omega-6 to omega-3 imbalance in Western diets is a documented concern, and while seed oils aren't toxic themselves, their frequent presence in ultra-processed foods contributes to overall unhealthy eating patterns. Always check food labels to avoid trans fats (partially hydrogenated oils) entirely.

Conclusion

Navigating the world of cooking oils can seem complex, but the key is to prioritize minimally processed, nutrient-rich options. Heart-healthy monounsaturated fats found in avocado and extra virgin olive oil offer the most significant benefits, with the former being an ideal choice for high-heat cooking. Certain oils, like flaxseed, excel in cold preparations. Conversely, oils high in saturated fats, like coconut and palm, should be used in moderation, while highly refined seed oils should be limited, particularly when they are heated repeatedly. By diversifying your oil selection and considering how each is used, you can make healthier, more informed culinary decisions. For the most part, a focus on whole foods and a balanced diet will naturally improve your fat intake. Eat Well Nutrition's advice is a great resource for further guidance.

Frequently Asked Questions

Coconut oil is highly controversial. It has a high saturated fat content, which can increase LDL ('bad') cholesterol. While it contains some beneficial medium-chain triglycerides (MCTs), it raises cholesterol more than unsaturated oils and should be used in moderation.

Some seed oils, like soybean and corn, are highly refined and high in omega-6 fatty acids. When heated repeatedly, they can become unstable and form potentially harmful compounds. The overconsumption of omega-6s, common in processed foods, can also contribute to an inflammatory imbalance.

The smoke point is the temperature at which an oil begins to burn and produce smoke. Heating an oil past its smoke point can produce harmful free radicals and ruin the flavor of your food.

Extra virgin olive oil has a medium smoke point (325-400°F), making it suitable for low-to-medium heat sautéing and baking, but not high-heat deep frying. For high-heat cooking, a more stable oil like refined avocado oil is a better choice.

Unrefined, cold-pressed oils are best for salad dressings as they retain their nutrients and flavor. Excellent choices include extra virgin olive oil, flaxseed oil, and walnut oil.

Most commercial 'vegetable oils' are highly refined blends of high-omega-6 seed oils like corn and soybean oil. While they are inexpensive and have a high smoke point, their refining process strips away nutrients, and they contribute to an imbalance of fatty acids when consumed in excess.

While the ideal omega-6 to omega-3 ratio is debated, a typical Western diet is very high in omega-6s. Instead of drastically cutting omega-6s, focus on increasing omega-3 intake from sources like fatty fish, flaxseed oil, and walnuts to achieve a better balance.