Are Seed Oils Really as Bad as They’re Made Out to Be?

Seed oils have gained a bad reputation in certain health circles, with claims that they’re harmful and directly linked to various health issues. But is this really the case? The truth is, seed oils are more complex than just “good” or “bad,” and they often serve as a proxy for other, larger issues in our diets and lifestyles.

What Are Seed Oils, Really?

Seed oils—like canola, soybean, and sunflower oils—are high in polyunsaturated fats, a type of fat with multiple double bonds in its structure. Polyunsaturated fats are different from monounsaturated fats (like those in olive oil) and saturated fats (found in butter and animal fats). Each type of fat behaves differently in the body, and research shows that polyunsaturated fats can have neutral or even positive effects on health, particularly when they replace saturated fats in the diet.

The Bigger Picture: Calories and Lifestyle

One of the main reasons seed oils are associated with poor health outcomes is that they’re commonly found in processed and fast foods, which are often calorie-dense and low in nutrients. This connection has led some people to assume that seed oils themselves are harmful, when in reality, they are often part of foods that contribute to overeating and an overall unhealthy diet. For example, when oils are used in deep frying, they add calories to foods, but so does the overall meal composition, especially in fast-food settings.

In short, seed oils may be acting as a proxy for unhealthy eating patterns rather than being uniquely harmful. It’s not the seed oils alone, but rather the high-calorie, low-nutrient foods they’re often found in, combined with a lack of exercise and overall poor diet quality, that can contribute to health issues.

Understanding the Complexities of Nutrition Science

Nutrition science is complex, and it’s challenging to make definitive statements about any one food or ingredient. In the case of seed oils, research doesn’t support the claim that they independently increase inflammation or lead to disease. Studies that have swapped saturated fats with polyunsaturated fats, like those in seed oils, have generally shown either neutral or positive effects on markers like cholesterol and blood pressure.

However, it’s important to note that cooking methods can affect the stability of oils. For instance, repeatedly heating oils at high temperatures, such as in deep frying, can lead to the formation of potentially harmful compounds. But again, this is more about how the oil is used rather than the oil itself.

The Bottom Line: Balance Over Extremes

Rather than demonising seed oils, a more balanced approach is to look at overall diet quality. Incorporating a variety of fats—monounsaturated, polyunsaturated, and even some saturated fats—in reasonable amounts is often the best way to support health. It’s also crucial to remember that, for most people, no single food or nutrient is solely responsible for health outcomes. Instead, it’s the overall pattern of what we eat, how much we move, and how we manage our lifestyle that matters most.

In nutrition, very few things are constant or black and white. As science progresses, we learn more about the complex mechanisms in our bodies and how they interact with different foods. Seed oils, like many other ingredients, should be viewed as one part of a much larger picture of health.