Some of the oils in question in Leveque’s post include soybean, corn, canola (rapeseed), sunflower (more details on the nuance of sunflower oil here), safflower, cottonseed, grapeseed, and rice bran. “Industrial seed oils were considered industrial waste and used only in soap making until 1911, but in the last 2 decades we’ve seen them added to everything from oat milk, protein bars, cookies, crackers, dip, dressings and prepackaged foods….plus all the fast casual and fast food restaurants use them to cook/fry everything,” she shares in her post.
These oils are made by heating the seeds to high temperatures, causing the polyunsaturated fats in the seeds (PUFA) to oxidize, which LeVeque says can create harmful byproducts for humans. “These seeds are then processed with a petroleum-based solvent such as hexane,” she says. “This is to maximize the amount of oil that can be extracted from those seeds.”
These oils are also chemically deodorized because, according to LeVeque, they smell like a mixture of fish and dirty feet, thus causing the production of trans fats (which are notoriously bad for human health.) After the addition of even more chemicals to improve the color, these seed oils ultimately can have a negative impact on our overall health.
“Between [the] years of 1959 and 2008 the increase [in] polyunsaturated fats, specifically linoleic acid has gone [up] 2 1/2 fold from 9.1% to 21.5%,” warns LeVeque. “We want a 1:1 ratio and we’re really far from that right now. When I was writing my first book in 2016 it was a 12:1 omega-6 to omega-3 ratio and today estimates have more than doubled.”