The Great Oil Debate: What You Need to Know About Cooking Fats

Pretty much all of us have a bottle or two of oil next to the stove or tucked into the pantry. We use oils and fats every day to fry, add flavor, and make dressings and sauces. However, this humble kitchen staple has become a surprising nutritional battleground. Are seed oils really bad for you, as some claim? Should we ditch olive oil in favor of ‘natural’ animal fats, as some wellness influencers urge us?

“It’s confusing,” admits Dr. Sarah Berry, a professor in the Department of Nutritional Sciences at King’s College London and chief scientist at the nutrition company ZOE. “From sunflower to olive to coconut oil, there are loads of options, and it’s tricky to know which are best to cook with.” So, what does the science say?

Sunflower, Safflower, and Rapeseed (Seed Oils)

These oils come from seeds like sunflower, safflower, and rapeseed (known as canola in the U.S.). They can be cold-pressed, where oil is squeezed directly from the seeds, or refined using heat and solvents. Some people worry that refined seed oils contain harmful chemicals, but Dr. Berry assures that this isn’t the case. “Based on current evidence, refined oils are very similar nutritionally to cold-pressed ones,” she says.

Seed oils are rich in heart-healthy unsaturated fats and contain phytonutrients and micronutrients, including vitamin E, a natural antioxidant. Critics often argue they’re inflammatory due to their high omega-6 content, particularly linoleic acid. However, large human studies show that people consuming more linoleic acid tend to have lower inflammation and reduced risks of heart disease and type 2 diabetes.

Moreover, trials indicate that increasing polyunsaturated fats can lower LDL (“bad”) cholesterol and cut cardiovascular disease risk by about 30%. The caveat here is not the oils themselves but how we consume them. “Seed oils are great,” Dr. Berry notes, “but if you’re eating them in ultra-processed foods like cakes and fast food, that’s definitely not healthy.”

For frying, rapeseed oil is particularly well-suited due to its richness in monounsaturated fats, making it more stable at high temperatures. Some critics raise concerns about overheating seed oils producing toxins, but Dr. Berry reassures us that under regular home-cooking conditions, this is not an issue.

Use for: Salad dressings, roasting, frying.
Definitely don’t: Worry about moderate use; just don’t assume they make processed foods any healthier.

Olive Oil

Dr. Federica Amati, a registered nutritionist and medical scientist, simplifies the matter: “There are no superfoods, but one food that outperforms anything else is extra virgin olive oil.” This oil is packed with natural polyphenols—powerful plant compounds that offer protection against inflammation and oxidation.

Research consistently links olive oil (especially extra virgin) to lower risks of cardiovascular disease, cancer, and premature death. Dr. Amati emphasizes the clear superiority of extra virgin olive oil for both cooking and dressing food. “You don’t need to worry about the boiling point,” she reassures, “since there are so many polyphenols in extra virgin olive oil that they counteract oxidative damage during cooking.”

Use for: Cooking, drizzling on salads, dips, finishing dishes.
Definitely don’t: Store in sunlight, which can slightly reduce its antioxidant benefits. Most olive oils come in tinted bottles for protection, though.

Avocado Oil

Extracted from the pulp of avocado, this oil contains the same heart-friendly, monounsaturated fats found in olive oil and boasts a high smoke point, making it suitable for frying. However, Dr. Berry remains cautious about the hype. “Avocado oil is marketed as having wonderful properties due to its high unsaturated fat content,” she explains. “But it’s really no different from rapeseed oil—just more expensive.”

Use for: Frying or salad dressings when a neutral flavor is desired.
Definitely don’t: Assume it’s a miracle oil; it’s healthy, but not superior to olive or seed oils.

Coconut Oil

This tropical oil, derived from coconut flesh, solidifies at room temperature and carries a distinctive flavor. It’s notably high in saturated fat—around 90%—which has been shown to raise LDL cholesterol levels more than plant oils.

“It’s quite controversial,” Dr. Berry comments. “Coconut oil is often marketed as healthy, but there’s little solid evidence to support that.” While the whole fruit may have some health benefits, the extracted oil isn’t recommended as a go-to for everyday cooking and has a relatively low smoke point, making it susceptible to burning.

Use for: Occasional flavor in baking or Asian-style dishes.
Definitely don’t: Rely on it as your main cooking oil. It’s less heart-friendly than olive or seed oils.

Butter

Natural and delicious, butter is hard to resist—especially on toast. However, it’s high in saturated fat, which can raise LDL cholesterol and increase long-term heart risks. A significant study published in JAMA Internal Medicine found that people consuming the most butter had a 15% higher risk of dying during the study compared to those who consumed the least, while those who favored plant oils had a 16% lower risk.

Replacing just 10 grams of butter daily with plant oil was associated with a 17% reduction in overall mortality, Dr. Amati adds. “Butter, especially from grass-fed cows, can be delightful and contains micronutrients like vitamins A, E, and D. Think of butter as an occasional splurge—perfect for toast or baking—but it shouldn’t be your main fat source.”

Use for: Baking, finishing sauces, spreading on toast.
Definitely don’t: Make it your primary cooking fat if you want to protect heart health.

Lard and Beef Tallow

Once kitchen staples, lard (from pork) and tallow (from beef) are returning to the limelight, often due to the influence of ancestral diet proponents. However, Dr. Berry isn’t convinced. “These fats are linked to poorer health outcomes,” she states. While they contain some vitamins, overall, they may raise LDL cholesterol and should be used sparingly.

Use for: Occasional roasting or frying when flavor is a priority.
Definitely don’t: Replace plant-based oils with these; animal fats are generally higher in saturated fat and less heart-friendly.

Low-Calorie Cooking Sprays

These sprays promise to help you fry with minimal calories. “In the past, low-fat diets were the go-to recommendation,” says dietitian Priya Tew. “But now, we know that this can lead to a less varied and nutritious diet.” Healthy fats are essential for absorbing fat-soluble vitamins like A, D, E, and K.

Some sprays can also contain additives that could be harmful. If you’re looking to cut back on oil without compromising cooking quality, consider pouring a little oil onto a paper towel and lightly greasing your pan instead of relying solely on sprays.

Use for: Quick, light greasing when absolutely necessary.
Definitely don’t: Depend on them as your primary cooking method. Healthy fats are essential, not the enemy.

In this modern age of conflicting dietary advice, understanding oils can feel overwhelming. Armed with insights from nutritional experts, you can make more informed choices about the fats you use in your cooking and enjoy a heart-healthy diet without compromising taste.