Claim: Seed Oils Are a Driving Cause of the Obesity Epidemic (and Beef Tallow is Better)

Verdict: False and highly misleading

“Seed oils are one of the driving causes of the obesity epidemic. Interestingly enough, this began to drastically rise around the same time fast food restaurants switched from beef tallow to seed oils in their fryers.”

Fast Food is a part of American culture. But that doesn’t mean it has to…

One of RFK Jr.’s long-running beliefs is that seed oils are a huge problem for society, and his comments have contributed to many restaurant and fast food chains moving away from seed oils. They often switch to beef tallow, which RFK’s nostalgia-drenched tweet also suggests is better.

But is seed oil really that bad? And is beef tallow better?

Why We Moved Away from Beef Tallow

Beef tallow (rendered cow fat) was more common historically, but the move to seed oils was primarily driven by concerns about cholesterol. As a recent JACC Advances editorial points out, beef tallow is high in saturated fat, and studies show that consuming beef tallow raises low-density lipoprotein cholesterol more than olive oil or corn oil.

It concludes that no evidence supports the idea that beef tallow is a healthier alternative to seed oils.

Do Seed Oils Cause Obesity?

There aren’t actually too many studies looking at this issue, but one systematic review and meta-analysis looked at 42 studies that addressed edible oils and weight gain. It found evidence that soybean, sunflower and rice oil were associated with the most weight gain, and generally that sesame and canola oil are linked with weight loss.

There are methodological issues, though. Notably, many studies didn’t account for overall calorie intake, and they often didn’t mention specific amounts of oil consumed either.

However, other reviews have also reached the same conclusion: some seed oils may actually reduce weight. And more importantly, large cohort studies strongly suggest that consumption of plant-based oils (including seed oils) reduces mortality compared to high-cholesterol options like butter. 

Why Seed Oils Look Bad for Obesity

So why the focus on seed oils? Simply, many unhealthy foods use seed oils, and seed oil consumption has increased alongside obesity rates. But correlation is not causation. You simply can’t ignore everything else we eat. If you’re at McDonald’s every day, it doesn’t really matter which oil they use.

Many aspects of American life have changed since RFK Jr.’s nostalgic beef tallow days. Bringing back the tallow won’t change those back too.