Are seed oils bad for you?
Short answer
The evidence is contested. Critics argue that refined seed oils supply far more omega-6 linoleic acid than humans historically ate and that high-heat refining produces oxidation products. Major nutrition bodies, including the American Heart Association, hold that replacing saturated fat with polyunsaturated oils lowers cardiovascular risk. No consensus exists, and Olive Detective does not claim one.
What the critics argue
The case against seed oils rests on three claims. First, that the omega-6 to omega-3 ratio in a modern diet is far outside the historical range, and that excess linoleic acid promotes inflammatory signalling. Second, that industrial refining — hexane extraction, bleaching, deodorising at high heat — generates oxidation and degradation products not present in cold-pressed fats. Third, that the rise of seed oils in the food supply tracks the rise of metabolic disease.
What the mainstream position says
Most major nutrition and cardiology bodies disagree with the strong version of that case. Randomised trials and meta-analyses generally find that swapping saturated fat for polyunsaturated fat lowers LDL cholesterol and cardiovascular events, and the direct evidence that dietary linoleic acid raises inflammatory markers in humans is weak. The third claim — that seed-oil consumption tracks metabolic disease — is a correlation that also tracks sugar, calories and ultra-processing.
Where the two sides quietly agree
Both sides agree on the practical thing: seed oils are overwhelmingly consumed inside ultra-processed food. A person cutting seed oils almost always cuts packaged snacks, fried fast food and industrial baked goods at the same time — and the benefit they feel may come from that, not from the oil itself.
That is why Olive Detective scores processing level and nutrition quality first and treats seed oils as one flag among several, rather than the whole verdict. If you want the seed-oil flag weighted heavily, you turn it on in your preferences and your personalised score reflects your choice, not ours.
What we will and won't tell you
Olive Detective flags where seed oils are, in which product, under which label name. It does not tell you they will make you ill, because that is not established, and it is not something an app should assert. What you do with the flag is a decision you make — ideally with a doctor or dietitian if you have a medical condition.
Frequently asked questions
- Does Olive Detective say seed oils are unhealthy?
- No. The app flags seed oils as a detected ingredient so you can decide, and it lets you weight that flag in your personalised score. The health score itself is driven mainly by nutrition quality and processing level, not by the seed-oil flag alone.
- Is there a safe amount of seed oil?
- No health authority has set an avoidance threshold for seed oils, because they are not classified as a hazard. Standard dietary guidance treats polyunsaturated oils as an acceptable fat source. Anyone with a specific medical condition should ask a clinician rather than an app.
More answers
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Last updated 26 August 2026.
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