Seed oils are the new tobacco — and you need to know about it

Oil crops have become some of the most profitable in agriculture and have changed the face of our planet. Yet, if we’re looking for smoking guns on what causes metabolic diseases in humans, seed oils are a high-probability harm factor, Eurof Uppington writes.

It’s been a creeping health crisis for decades. Seed oils, highly refined industrial fats, are almost unavoidable in our diets. They are also one of the single biggest sources of total calorie intake and drivers of epidemics of ill health. And we need to know about it.
Previously the bugbear of a mix of concerned scientists, right-wing carnivores, and podcast hosts, seed oil awareness hit the big time in the US late last year: healthy lunchtime salad bowl brand Sweetgreens announced it was taking seed oils off the menu for cooking, citing health concerns, and was going to use Californian extra virgin olive oil instead. Other chains have followed.
In the US, there are now apps to find seed oil-free restaurants, a new “seed oil-free” food certification, and startups, like Zero Acre Foods, pushing novel cooking oils with no seeds in sight.
Full disclosure: I run a B2B regenerative olive oil company. This is why I started researching cooking oils in our food system. What I discovered truly shocked me and changed the way I eat. I’m passing it on.
What are seed oils? Why are they bad? 100 years ago, before P&G first started selling Crisco, a refined cottonseed oil derivative, as a food product, frying was only possible with animal products like lard or butter or plant-based oils, such as olive or palm, which were sometimes expensive or hard to get.
Other novel and cheap food oils followed, and now we consume vast amounts of sunflower, soybean (aka “vegetable oil”), canola or colza, grapeseed, peanut, and corn oils.
These are all polyunsaturated oils made from seeds. The oils are chemically extracted, heavily refined, and bleached in factories that resemble petroleum refineries.
This processing is part of the problem with seed oils. Industrial extraction and purification processes pre-heat the long-chain fatty acids they’re made of and remove protective antioxidants.
When heated again, the chains can break down into more harmful by-products, such as trans fats or polar compounds, which cause oxidative stress in animal and human cells — associated with cancer, diabetes, heart disease, and a list of other metabolic diseases.
The longer and more often these oils are heated, say in deep fat fryers, the more harmful the compounds created. Moreover, polyunsaturated fats are more likely to break down than saturated (like butter) or monounsaturated (like olive oil) ones.
This is noncontroversial food science. It’s why cooking oil in fryers should be changed regularly. In Europe, this is regulated: fryer oil must be tested for total polar materials (TPM) using probes.
Once TPMs reach 24% to 27% of the oil volume, sometimes after about 10 uses, the oil should be changed. Deep fryers in some countries aren’t allowed to use canola, sunflower, or vegetable oil.
In Switzerland, where I live, food safety agencies take this extremely seriously.
In the US there’s no such regulation, however, and fryer oil is often reused for weeks, just filtered for bits of batter or potato. The oil is mostly only changed when it changes colour, a test not considered safe in Europe.
However, seed oils are not just ubiquitous in restaurants. They’re now fully present in almost all highly- and ultra-processed foods, from plant-based meat and dairy to snacks to chocolate and confectionery, having replaced olive, palm and animal fats in almost everything ready-made that we buy. They’re simply cheaper.
With the rise of processed foods in our diets, almost 30% of the calories now consumed in the US and UK come from seed oils. Europe is behind, but not by much. That’s up from roughly zero 80 years ago. In the history of human diets, this is a very new and significant change.
The increase in seed oil consumption coincides neatly with the rise of metabolic disease in the developed world. Animal experiments have demonstrated cellular pathways where high polyunsaturated oil consumption induces cell oxidation, leading to fat deposits, obesity, and chronic inflammation, pathways that are missing with more stable fats.
Humans are not mice, however, and a causal link between seed oil and metabolic diseases in humans hasn’t yet been proven. Other scientists point to increased sugar and ultra-processed food consumption as potential culprits.
Other factors like pesticides, microplastics, and even chemical contrails have all been mentioned. But if we’re looking for smoking guns, seed oils are a high-probability harm factor, as well as being implicated in ultra-processed food.
Nevertheless, this wiggle room allows the food industry to continue using seed oils in increasing quantities. Oil crops have become some of the most profitable in agriculture and have changed the face of our planet — witness the loss of rainforest from the rise of soy cultivation in Brazil or the sudden appearance of yellow rapeseed fields across the northern hemisphere from the 1990s on.
What can we do? What does a seed oil-free diet look like? It’s very much like what our grandparents used to eat: whole foods processed at home. Using lots of olive oil is good, and butter, too.
Be suspicious of fries in restaurants. Ask waiters what oil the chef uses and ask which menu items are seed oil-free. In the US, look for the Seed Oil Free Alliance’s certification.
Most of all, read the ingredients of what you buy in shops, something we should be doing anyway.
While much of Europe has yet to notice, food trends in the US often quickly spread here. With better regulation and stronger local food cultures, the extent of the problem may be less in Europe, but it still exists and is increasing.
Get ahead of the trend, why not? Your friends might think you’re weird now, but they may be impressed later.
Eurof Uppington is the CEO and Founder of Amfora, a Switzerland-based importer of extra virgin olive oils.
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