STAT shared the words of a frustrated cardiac dietitian who is personally exhausted by the public panic over seed oils, which, depending on how you look at them, really are healthier than the alternatives:
First, “seed oils” is a marketing term, not a nutritional category. What we’re actually talking about are vegetable oils high in polyunsaturated and monounsaturated fats — the kinds of fats that, in decades of research, are associated with lower rates of cardiovascular disease when they replace saturated fat in the diet. A 2020 Cochrane meta-analysis of roughly 59,000 participants across 15 randomized controlled trials found that replacing saturated fat with polyunsaturated fat reduced combined cardiovascular events by 21%. Cardiologists note that the risk reduction from this dietary substitution is comparable to the benefits of statin medications. We don’t make a habit of telling statin patients to stop their medication because of something they heard on a podcast.
The core claim of the seed oil panic is that linoleic acid — an omega-6 fatty acid in these oils — drives systemic inflammation, which drives chronic disease. It sounds plausible. But “sounds plausible” and “is demonstrated in humans at dietary exposure levels” are different things. Randomized controlled trial evidence does not support this claim.
There’s a secondary argument about oxidation — seed oils go rancid at high heat, producing potentially harmful compounds. This idea is chemically real and worth being thoughtful about (don’t reuse frying oil repeatedly). But the evidence that oxidation at home-cooking levels causes measurable harm in humans isn’t there.
Some of what’s driving the seed oil panic isn’t wrong — it’s just misattributed. Ultra-processed food really is a problem. The National Institutes of Health published the first randomized controlled trial on ultra-processed food in 2019 (a landmark study by Kevin Hall’s team) showing that people randomized to an ultra-processed diet consumed about 500 more calories per day and gained weight, even when macronutrients were matched precisely. The food was engineered to override satiety — proven, not suggested.
But seed oils are not why ultra-processed food behaves that way. They are but one ingredient in a complex and highly engineered product designed to keep you eating past fullness. The oil isn’t the villain; the food product surrounding the oil is. Blaming seed oils for the harms of ultra-processed food is as helpful as blaming the wrapper.