The Evidence on Seed Oils
Don't take our word for it. Below is the free, readable evidence behind cutting seed oils — starting with Ray Peat, then the strongest controlled trials, the mechanism, and the doctors and researchers making the case. Every link opens something you can read or watch for nothing. Read it and decide for yourself.
Ray Peat, Ph.D.
The biologist and endocrinologist who first made the case, in plain writing, that the polyunsaturated fats in seed oils quietly damage metabolism and health. For this community, he is where it started — and all of his work is free to read.
The trials that swapped them in
In the two best controlled trials that replaced saturated fat with seed-oil linoleic acid, cholesterol fell — but people did not live longer, and the seed-oil groups actually had more deaths. Both are peer-reviewed and open-access.
🧬 Start Here: Ray Peat
The biologist whose writing put polyunsaturated seed oils at the center of this whole conversation. Everything on his site is free to read.
| Unsaturated Vegetable Oils: Toxic Ray Peat, Ph.D. — His foundational essay — why the polyunsaturated fats in seed oils suppress metabolism, the thyroid, and the immune system. The piece most people start with. | FREE |
| The Great Fish Oil Experiment Ray Peat, Ph.D. — Why "healthy" polyunsaturated oils — including fish oil — drive the same oxidation damage as the seed oils they were supposed to replace. | FREE |
| Every Ray Peat article (full archive) Ray Peat, Ph.D. — His complete library of free articles on fats, hormones, metabolism, and health. Decades of writing, all openly available. | FREE |
🔬 The Strongest Hard Proof
The best evidence is not an opinion — it is the controlled trials. In the two best-run experiments that actually swapped saturated fat for seed-oil linoleic acid, cholesterol dropped but people did not live longer. Both are peer-reviewed and free to read in full in The BMJ.
| Minnesota Coronary Experiment — recovered data (BMJ, 2016) Ramsden, Zamora, et al. — A large 1968–73 randomized trial, re-analyzed from recovered records. Replacing saturated fat with corn oil lowered cholesterol — yet the corn-oil group had no survival benefit and a higher risk of death. The single most-cited study in this debate. | FREE |
| Sydney Diet Heart Study — recovered data (BMJ, 2013) Ramsden, et al. — Men who replaced saturated fat with safflower-oil linoleic acid died at HIGHER rates from heart disease and all causes than the control group. A randomized trial, re-analyzed and published open-access. | FREE |
⚗️ Why It Happens: The Mechanism
The "how": linoleic acid (the main fat in seed oils) is chemically unstable. In the body it oxidizes into reactive compounds (OXLAMs, 4-HNE) that damage cells, LDL, and mitochondria. These are the peer-reviewed papers behind that claim.
| Oxidized linoleic acid metabolites — the research (PubMed) Ramsden, et al. & others — A free PubMed index of the studies on how dietary linoleic acid oxidizes into harmful metabolites linked to pain, inflammation, and cardiovascular damage. Abstracts free; many are full open-access. | FREE |
🩺 The Doctors & Researchers Making the Case
Clinicians and independent researchers who argue that industrial seed oils are a primary driver of modern chronic disease. Each keeps a free public library.
| Chris Knobbe, MD — "Diseases of Civilization" Ophthalmologist & researcher — Argues seed oils are the proximate cause of macular degeneration and other chronic disease. His foundation hosts free talks and references. | FREE |
| Cate Shanahan, MD — the "Hateful Eight" oils Family physician, author of "Dark Calories" — Coined the "Hateful Eight" seed oils. Her site has a deep library of free articles explaining the science for a general reader. | FREE |
| Nina Teicholz — "The Big Fat Surprise" Investigative science journalist — Documented how the evidence for replacing animal fat with vegetable oils was far weaker than the public was told. Free articles and reporting. | FREE |
| Tucker Goodrich — the mechanistic case Independent researcher — Tracks and explains the published literature on linoleic acid and oxidation. A free, heavily-sourced archive for people who want the primary papers. | FREE |
| The Weston A. Price Foundation Nonprofit nutrition foundation — A large free archive of articles on traditional fats vs. industrial seed oils, with citations throughout. | FREE |
▶️ Watch & Listen (free)
Prefer video? These are free to stream.
| Chris Knobbe — "Diseases of Civilization" lecture Full presentation — The hour-long talk that lays out the seed-oil / chronic-disease thesis with charts and citations. Free on YouTube. | FREE |
The short version
Seed oils (soybean, canola, corn, sunflower, safflower, cottonseed) are very high in linoleic acid — an unstable polyunsaturated fat that oxidizes easily, inside the body and out. The researchers and clinicians above argue that flooding the modern diet with it is a primary driver of chronic disease, and that traditional fats — beef tallow, butter, olive oil — don't carry the same risk. The sources here are the primary studies and free libraries this case rests on, gathered in one place so you can check them yourself.