Why Seed Oils Became One of the Most Misunderstood Foods, Says Dietician James Brash

For years now, seed oils have been cast as the quiet villain of modern eating. Scroll through social media, and you will find warnings about “industrial processing,” inflammation, and claims that seed oils are behind everything from weight gain to chronic disease. But registered dietitian James Brash says most of this fear is misplaced — and often misses the bigger picture of what actually matters for everyday health.

Brash, founder of Brash Nutrition, says conversations around seed oils have become far more dramatic than the science supports. “There are a lot of things people are worried about that they genuinely don’t need to be,” he explains, pointing out that nutrition misinformation often thrives on oversimplification.

The omega-6 confusion

One of the most common criticisms of seed and vegetable oils is their omega-6 content. According to Brash, this is where fear tends to snowball. “Seed oils are a source of omega-6, and people hear that word and immediately think inflammation,” he says. “But omega-6 fats are essential. We actually need them.”

He explains that omega-6 fats are broken down into arachidonic acid, which helps form inflammatory compounds in the body. But inflammation itself is not automatically bad. “Inflammation is part of how the immune system works,” Brash says. “The presence of omega-6 doesn’t mean your body is constantly inflamed.”

Brash adds that research has not shown that typical seed oil intake increases chronic inflammation. “The idea that seed oils on their own are driving inflammation just isn’t backed by evidence,” he notes.

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Seed oils aren’t the real problem with ultra-processed foods

Another common argument is that seed oils are unhealthy because they are often used in ultra-processed foods. Brash says this connection is often misunderstood. “Seed oils are found in ultra-processed foods, but that’s not what makes those foods unhealthy,” he explains.

According to him, the issue with ultra-processed foods is their overall nutritional profile—not any single ingredient. “It’s the excess sodium, refined carbohydrates, low fiber, and overall calorie density that matter,” Brash says. Blaming seed oils, he argues, distracts from addressing broader dietary patterns.

He stresses that removing seed oils alone won’t suddenly turn a diet healthy. “You can’t isolate one ingredient and ignore the rest of the context,” he adds.

What actually helps heart health

Where Brash becomes most direct is when discussing fat quality. “Replacing saturated fats like butter and ghee with unsaturated fats, including seed oils, is consistently shown to reduce cardiovascular disease risk,” he says.

He explains that large-scale studies link this swap to improved cholesterol levels and better long-term heart health. “This isn’t about trends,” Brash notes. “This is about decades of nutrition research.”

Brash recommends that fat should make up roughly 30 per cent of daily calories, while saturated fat should stay below about 10 per cent. “That balance allows room for oils like canola, sunflower, and soybean without pushing out other important nutrients,” he says.

Rather than fearing seed oils, Brash encourages people to zoom out. “Nutrition doesn’t work in extremes,” he says. “It’s about patterns over time, not moralizing individual foods.”

In a food culture driven by headlines and hot takes, Brash’s message is refreshingly grounded. Seed oils, he says, don’t need defending — they need context.