Do read the whole thing (subscription required for full post, but the analysis is in the free part), but here are some choice quotes (all bold)
“Problem #1 - they do not actually know how much butter people are eating. Everyone is assumed to use the exact same amount (a pat 5 g) of butter every time they report using it. This means a butter croissant is the same as butter on toast versus butter in the pan before you sauté a chicken. Anyone who cooks will know that this is an idiotic assumption.”
That’s not all…
“They justify this by citing a paper (ref 24) saying their method of conversion has been “validated” but I read that paper, and it is sobering. By validated, they means that food frequency has some weak correlation with another imperfect method of data collection— a 7 day diary. (which PS might also not be accurate) And when I pull the figures in the paper, I found they were even more dishonest. Butter is actually one of the ones where there is the weakest correlation between frequency and amount based on diary. And the true amount consumed is likely EVEN MORE INACCURATE than this, so the real correlation is even worse.”
They likely have the same problem with the oils, they don’t know how much people are really eating.
“Related problem, is I see no validation for these oils in the paper. In other words, just as with butter, I could not find strong support that they are accurately measuring intake of these oils.”
They’re imputing the amount of oil based on food composition guesses. “He said he ate salad dressing, let’s presume it was soybean oil and not cottonseed oil…”
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Prasad continues:
“Problem #2 - they combine OLIVE oil with these other oils.”
This is the same con they pulled with this other paper by some of the same authors.
They combined the good stuff (potatoes not cooked with seed oils) with the bad stuff (potatoes fried in seed oils) to make the bad stuff look better.
Zhang et al.’s reference from the AHA (Sacks, 2017) does the same thing with Ω-6 and Ω-3, and was called out for it after the AHA’s 2009 paper (Harris, 2009)
“Although the AHA Advisory [1] criticizes other studies for failing to distinguish between “distinct effects” of omega-3 and omega-6 fatty acids, it commits this error throughout.” (Hibbeln, 2009)
Prasad makes some other great points, including to note that the NIH funding this paper is a scandal.
This may be the best bit:
“Finally, these three authors in particular have done some of the worst science of the last 50 years. Go ahead, pull their papers and see for yourself. It proves how careers are made of bad nutritional epi.”
Do read the whole thing.
References
Harris, W. S., Mozaffarian, D., Rimm, E., Kris-Etherton, P. M., Rudel, L. L., Appel, L. J., Engler, M. M., Engler, M. B., & Sacks, F. (2009). Omega-6 Fatty Acids and Risk for Cardiovascular Disease: A Science Advisory From the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention. Circulation, 119(6), 902–907. https://doi.org/10.1161/CIRCULATIONAHA.108.191627
Hibbeln, J. R., Lands, W. E. M., Ramsden, C. E., Tribole, E., Harris, W. S., Mozaffarian, D., Kris-Etherton, P. M., Sacks, F. M., Rudel, L. L., & Appel, L. J. (2009). Various letters regarding "Omega-6 fatty acids and risk for cardiovascular disease: A science advisory from the American Heart Association Nutrition Subcommittee of the Council on Nutrition, Physical Activity, and Metabolism; Council on Cardiovascular Nursing; and Council on Epidemiology and Prevention. ". Circulation.
Sacks, F. M., Lichtenstein, A. H., Wu, J. H. Y., Appel, L. J., Creager Mark, M. A., Kris-Etherton, P. M., Miller, M., Rimm, E. B., Rudel, L. L., Robinson, J. G., Stone, N. J., Van Horn, L. V., & on behalf of the American Heart Association. (2017). Dietary Fats and Cardiovascular Disease: A Presidential Advisory From the American Heart Association. Circulation, 136(3), e1–e23. https://doi.org/10.1161/CIR.0000000000000510
Zhang, Y., Chadaideh, K. S., Li, Y., Li, Y., Gu, X., Liu, Y., Guasch-Ferré, M., Rimm, E. B., Hu, F. B., Willett, W. C., Stampfer, M. J., & Wang, D. D. (2025). Butter and Plant-Based Oils Intake and Mortality. JAMA Internal Medicine. https://doi.org/10.1001/jamainternmed.2025.0205
'They combined the good stuff (potatoes not cooked with seed oils) with the bad stuff (potatoes fried in seed oils) to make the bad stuff look better.'
They manage this by lumping the better fruit oils (coconut, avocado, olive) in their category of "plant oils" which, of course includes the high-linoleic seed oils.
Tucker, do you remember one of these several years back where it was discovered that ice cream was included in the "meat" category on the surveys? (It goes without saying that the headline was MEAT BAD FOR YOU!!!!)
'They combined the good stuff (potatoes not cooked with seed oils) with the bad stuff (potatoes fried in seed oils) to make the bad stuff look better.'
They manage this by lumping the better fruit oils (coconut, avocado, olive) in their category of "plant oils" which, of course includes the high-linoleic seed oils.
Tucker, do you remember one of these several years back where it was discovered that ice cream was included in the "meat" category on the surveys? (It goes without saying that the headline was MEAT BAD FOR YOU!!!!)