Plant oils are “the biggest villain” out of “all the bullshit foods”. Not our words, but those of major health influencer (and big fan of raw milk) Dr Paul Saladino.
Extreme? Very likely. But Saladino’s anti-seed oil stance is no longer fringe. He’s joined in that opinion by swathes of dieters and nutritionists – as well as the US health secretary Robert F Kennedy Jr.
Kennedy has called seed oils “one of the most unhealthy ingredients that we have in foods,” and has advocated for the return of butter, tallow and lard to American diets, claiming that seed oils promote inflammation in the body.
It’s a sentiment reflecting a broader shift in eating habits, says Prof Thomas Sanders, nutrition scientist at King’s College London: “In the last few years, butter has come back on the menu. People are going back to full-fat milk, going back to eating butter.”
This is particularly true in the US, where the Department of Agriculture has reported steadily increasing levels of butter consumption in recent years, reaching a record 3kg (6.8lbs) – that’s the weight of a newborn baby – per person in 2024.
And these trends are worrying health professionals. That’s because, despite all the butter hype, the evidence still suggests that plant oils are a healthier choice.
“The evidence is really consistent,” says Prof Sarah Berry, nutrition scientist at King’s College London. “Randomised controlled trials show that plant oils are better for you, and butter is worse for you.”
Here’s why…
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The hidden problem with butter
So, what’s the problem with the return to butter, tallow and lard? Well, they all contain saturated fat. A lot of saturated fat.
As you’ve probably heard, saturated fat is considered the ‘worst’ fat for our health – and for good reason.
Each saturated fat molecule is made up of a chain of carbon atoms, joined together with as many hydrogen atoms as possible. The carbon is therefore ‘saturated’ with hydrogen.
That might not sound bad, but it has a big impact on your cholesterol levels.
Compared to unsaturated fats (which have a slightly different molecular make-up), saturated fat triggers your body to release more LDL cholesterol (known as the ‘bad’ kind) into your blood.
Extra LDL cholesterol in your bloodstream means a higher risk of heart disease – which is why saturated fats are associated with worse heart health.
And there’s a wealth of evidence to back this up. For example, a recent Harvard study, analysing data on 221,000 people, found that eating more butter was associated with a higher risk of heart disease, cancer and early death – and eating more plant oils was associated with a lower risk of early death.
The paper estimated that every 10g of butter that a participant ate per day – instead of 10g of plant oils – increased their risk of dying during the 30-year study by 17 per cent.
(It’s important to note this research is just an observational study, so it could be that those who ate more plant oils just had a healthier overall diet.)
That’s just one study, but countless others point to the same thing over and over again: eating a lot of saturated fat is linked to worse heart health.
However, that’s not to say that all saturated fat is equal.
“The dairy fat in milk and cheese and yoghurt seems to be slightly different to butter,” explains Sanders. “It doesn’t have as big a cholesterol-raising effect as butter does. Milk and cheese seem to be quite neutral, and it’s thought other nutrients in cheese and milk mitigate the effect of saturated fat.”
So, even if you have slabs of cheese and butter that contain similar amounts of saturated fat, the butter – not the cheese – is likely to affect your cholesterol levels.
On the other hand, says Berry, “plant oils are rich in mono and polyunsaturated fats that are really potent in lowering your cholesterol and reducing your risk of cardiovascular disease.”
'But seed oils are inflammatory!'
So far, it’s 1-0 in favour of plant oils – but these fats are accused by the likes of RFK Jr of something potentially harmful too: causing inflammation in the body. What say the scientists to that?
In short, they say it’s not true. The supposed culprit is omega-6, some of which gets converted in the body to a substance called arachidonic acid.
This long-named acid does have some inflammatory effects – but Sanders says it has some anti-inflammatory properties too, so “there’s a bit of a yin and yang between the two.”
And the upshot is that, while it’s true that eating a lot of seed oil could promote inflammation, the evidence currently suggests that it doesn’t.
Instead, a 2019 meta-analysis of 30 studies found that higher levels of omega-6 in fat tissue were associated with lower risk of heart disease, heart attacks and strokes.
Sanders adds that omega-6 is “good” and “an essential nutrient.”
'Butter is natural, but seed oils are processed'
Plant oils might not cause inflammation via omega-6, but that’s not the only anti-oil belief to address.
Another argument that is often levelled against plant oils is that they are processed, relatively new foods devoid of nutritional value, while butter is a natural, traditional food.
But Sanders says that’s not true either: “Seed oils have been used for millennia. If you go back to ancient civilisations in the Middle East, you’ll find evidence that they were using safflower oil medicinally. And the Chinese used soybean oil and groundnut oil for a long, long, long time.”
Of course, modern plant oils are processed differently from how they were in the past – but Berry says it’s nothing to worry about.
“Scary words are used about the refinement process, like bleaching and deodorisation,” she says. “We’re not using bleach. It’s just a term for the process it goes through.”
That process involves heating the oil to a specific temperature, and then treating it with activated clays, until it’s a certain colour.
The result, she says, is a shelf-stable refined oil. True, it will contain fewer nutrients – such as vitamin E or polyphenols – compared to traditionally cold-pressed oils. But it’s still “a really healthy oil”.
You don't even need to worry about margarine
So, the key accusations levied against plant oils don’t seem to hold up. But, while plant oils have their fair share of haters, margarine is often demonised by a circle of health influencers.
For instance, Saladino called margarine “garbage” in an Instagram reel in March 2025, instructing his followers: “Don’t ever touch it. Don’t ever buy it. Don’t ever look at it.”
This anti-marg vitriol used to be justified. Back in the day, the spread was seriously unhealthy.
That’s because it contained trans fats: previously liquid oils that had been altered so they were solid at room temperature.
“Trans fats are really bad for us,” says Berry. “They raise cholesterol, they increase inflammation, they increase your risk of multiple diseases.”
But today, margarines don’t contain trans fats. At all. Manufacturing methods have moved on.
“I would absolutely advocate for changing from butter to margarine,” says Berry. “The evidence is clear that it’s better for you.”
Don't throw the butter out with the bathwater
From saturated fat to processing methods, there are myriad reasons why plant oils would fare better than butter in a health contest.
So, should we stock up on sunflower oil to maximise the benefits? Actually, no. Like most foods, plant oils are good for us in moderation – and most of us are eating too much already.
“The only problem I have with vegetable oil is that people are eating too much, in crisps and other foods that are not important parts of the diet,” says Sanders. “If you eat a 40g bag of crisps, a third of that is going to be vegetable oil, which is extra calories.”
That means that, for a standard bag of ready salted crisps – which is actually 25g or 0.9oz in the UK – 45 of its 135 calories come straight from its 8g of oil, or roughly half a tablespoon.
Berry agrees, adding: “About 60 per cent of the seed oil that we eat is found in quite unhealthy, heavily processed products, so we should be reducing those products – but not because of the seed oil; because they’re high in added sugars and salt and low in fibre.”
As with so many things, moderation is key here – even with an oil associated with longevity, healthy ageing and lower risk of metabolic diseases.
Similarly, there’s nothing wrong with enjoying butter in moderation. Sanders says, if you’re having “a little pat of butter on your toast” or using a small lump to flavour your vegetables, that won’t make much difference to your overall health.
Sanders concludes: “You can have a little bit of butter… but it’s better to have more vegetable oil.”
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