Study Reports Rapid Arterial Plaque Growth In Keto Dieters
- Patrick Elliott, BSc, MPH
- 2 days ago
- 7 min read
A new study has reported rapid arterial plaque growth in a group of ‘metabolically healthy’ keto dieters. But you might not have known that if you read the study…
Introduction
It’s pretty uncontroversial to say that plant-rich diets—be that the traditional Mediterranean diet, Nordic diet, plant-based diets, or what you see recommended in dietary guidelines around the globe—are optimal for supporting long-term health for most people. In fact, a study recently published in the journal Nature Medicine reported a greater likelihood of healthy aging (i.e., reaching 70 years of age without major chronic disease or impairments in cognitive, physical, or mental health) for those adhering closer to a variety of plant-rich dietary patterns compared to those adhering less closely (1).
Despite this, there are many stories online describing people who switched to animal-based diets, including ketogenic and carnivore diets, and feel much better. In fact, some people report improvements in a variety of health conditions and markers—leading them to better metabolic health. However, there’s often one commonality among these individuals: their LDL cholesterol (sometimes called ‘bad’ cholesterol) skyrockets. This is bad news: there is unequivocal evidence that LDL cholesterol causes plaque to build up in the arteries, ultimately increasing risk of heart disease (2).
In spite of this overwhelming evidence, a small group of researchers believe that context is important, and that those who are in peak metabolic health and who experience this giant increase in LDL cholesterol may be protected from the risks of such high levels of LDL cholesterol and, thus, may not be at higher risk of heart disease. However, they have just published a study that suggests otherwise.
It is always important to keep in mind that for every positive story about an extreme diet like the carnivore diet, there’s likely to be a negative story (see Carnivore Cringe on Instagram, for example). That’s why we investigate the healthfulness of any diet through rigorous research, not personal anecdotes.
The KETO-CTA Study
The KETO-CTA Study was a one-year observational study, where researchers measured arterial plaque in individuals with ostensible peak metabolic health at baseline (but sky-high LDL cholesterol), and did this again one year later (3). Prior to conducting this study, the researchers pre-registered their plans, where they listed the following as their primary outcome (which is basically the main thing the researchers were interested in looking at): ‘Percent change in total non-calcified coronary plaque volume from baseline (start of the study) till the final visit will be measured using Coronary Computed Tomography Angiography (CCTA).’ Sounds good. Upon reading, however, you’d be forgiven if you missed any mention of this outcome in the text—because it was left out.
If purposeful, this is extremely unethical behaviour, and the reaction to this study online has rightly been quite damning. In light of pressure from other academics, researchers, and clinicians, the lead researcher of this study has since posted the primary outcome… on Twitter (Figure 1)! You couldn’t make this up. The Tweet indicated that non-calcified plaque volume (which is basically the soft, fatty buildup of plaque in your arteries that hasn’t turned hard yet) increased by a median of 18.8 mm3 (or ~43% from baseline), which is about 4 times higher than the yearly increase in the NATURE-CT study (which included generally healthy individuals) (Figure 2) (4), and is about 2.5 times higher than what these authors predicted they would observe in their protocol paper (5).
Figure 1. The lead author’s Tweet, where he shared the primary outcome of the KETO-CTA study.
Figure 2. Absolute change in non-calcified plaque volume in KETO-CTA participants compared to the annualised change observed in healthy participants in the NATURE-CT study (6).
Not only that, but another measure of plaque buildup known as percent atheroma volume increased by 0.8% (3). This is greater than what was observed in individuals at low and intermediate risk of heart disease in the PARADIGM study (Figure 3) (7), and is similar to the annualised growth that has been previously associated with greater risk of major cardiovascular events (e.g., heart attacks) (Figure 3) (8).
Figure 3. Relative change in percent atheroma volume in KETO-CTA participants compared to low, intermediate, and high-risk groups in the PARADIGM study and the annualised increase that was associated with future major adverse cardiovascular event risk in the PARADIGM study (6).
This doesn’t look good for animal-based ketogenic diets, and these findings would seem to reaffirm the reality of the independent plaque-raising quality of elevated LDL cholesterol—despite the fact that the authors reported no relationship between LDL cholesterol and plaque growth in this study (3). But their analysis doesn’t make sense, as everyone had high levels. It would be like saying stabbing isn’t related to death if you compared those stabbed 40 times to those stabbed 60 times (because unless a miracle happens, those stabbed 40 times will be as dead as those stabbed 60 times). What you would need to do is compare those stabbed 40 or 60 times to those not stabbed at all, or maybe once or twice, if you wanted to truly investigate this relationship. In the same way, you would need to compare these keto dieters with sky-high LDL cholesterol levels with a group of similar individuals with low levels of LDL cholesterol if you wanted to assess this relationship.
Summary
Individuals eating animal-based ketogenic diets who experience a big rise in LDL cholesterol levels (and who are otherwise metabolically healthy) gain plaque in their arteries rapidly, and do not seem to be protected from the deleterious heart health impacts of high LDL cholesterol despite their otherwise pristine health. Myself and colleagues have published a commentary paper on this study that goes into more detail (6), so do check that out if you are interested.
I haven’t even gotten into the bizarre communication of this study online by its authors, and there are many more issues at play (see this video from Dr Gary McGowan for a comprehensive overview of this entire fiasco). But the high-level takeaway for anyone interested in eating a heart-healthy diet is to eat a plant-rich diet that doesn’t skyrocket your LDL cholesterol and which supports long-term health. For more insight into what that may look like, check out our previous articles on Diet and Health.
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Thanks so much for reading!
Patrick Elliott, BSc, MPH
Health and Nutrition Science Communication Officer at Training121
Instagram: @just.health.info
Twitter/X: @PatrickElliott0
References
(1) Tessier AJ, Wang F, Korat AA, Eliassen AH, Chavarro J, Grodstein F, Li J, Liang L, Willett WC, Sun Q, Stampfer MJ, Hu FB, Guasch-Ferré M. Optimal dietary patterns for healthy aging. Nat Med. 2025. Available at: https://www.nature.com/articles/s41591-025-03570-5
(2) Ference BA, Ginsberg HN, Graham I, Ray KK, Packard CJ, Bruckert E, Hegele RA, Krauss RM, Raal FJ, Schunkert H, Watts GF, Borén J, Fazio S, Horton JD, Masana L, Nicholls SJ, Nordestgaard BG, van de Sluis B, Taskinen MR, Tokgözoglu L, Landmesser U, Laufs U, Wiklund O, Stock JK, Chapman MJ, Catapano AL. Low-density lipoproteins cause atherosclerotic cardiovascular disease. 1. Evidence from genetic, epidemiologic, and clinical studies. A consensus statement from the European Atherosclerosis Society Consensus Panel. Eur Heart J. 2017;38(32):2459–72. Available at: https://academic.oup.com/eurheartj/article/38/32/2459/3745109
(3) Soto-Mota A, Norwitz NG, Manubolu VS, Kinninger A, Wood TR, Earls J, Feldman D, Budoff M. Plaque Begets Plaque, ApoB Does Not: Longitudinal Data From the KETO-CTA Trial. JACC Adv. 2025:101686. Available at: https://www.sciencedirect.com/science/article/pii/S2772963X25001036
(4) Aldana J, Kinninger A, Krishnan S, et al. Abstract 4139340: Atherosclerotic Plaque Progresses Over Time in Healthy Individuals Without MACE, Risk Factors, or Interventions. Circulation. 2024;150:Suppl 1. Available at: https://www.ahajournals.org/doi/10.1161/circ.150.suppl_1.4139340
(5) Javier DAR, Manubolu VS, Norwitz NG, Kinninger A, Aldana-Bitar J, Ghanem A, Ahmad K, Vicuna WD, Hamidi H, Bagheri M, Elsayed T, Villanueva B, Ichikawa K, Flores F, Hamal S, Feldman D, Budoff MJ. The impact of carbohydrate restriction-induced elevations in low-density lipoprotein cholesterol on progression of coronary atherosclerosis: the ketogenic diet trial study design. Coron Artery Dis. 2024;35(7):577–83. Available at: https://journals.lww.com/coronary-artery/fulltext/2024/11000/the_impact_of_carbohydrate_restriction_induced.6.aspx
(6) Kirwan R, Elliott PS, Flanagan A, McGowan G, Nagra M, Mughal I, Nadolsky S. Rapid Plaque Progression Amongst Lean Mass Hyper-Responders Following a Ketogenic Diet with Elevated ApoB and LDL-Cholesterol. OSF. 2025. Available at: https://osf.io/preprints/osf/78bph_v1
(7) Han D, Berman DS, Miller RJH, Andreini D, Budoff MJ, Cademartiri F, Chinnaiyan K, Choi JH, Conte E, Marques H, de Araújo Gonçalves P, Gottlieb I, Hadamitzky M, Leipsic J, Maffei E, Pontone G, Shin S, Kim YJ, Lee BK, Chun EJ, Sung JM, Lee SE, Virmani R, Samady H, Stone P, Narula J, Bax JJ, Shaw LJ, Lin FY, Min JK, Chang HJ. Association of Cardiovascular Disease Risk Factor Burden With Progression of Coronary Atherosclerosis Assessed by Serial Coronary Computed Tomographic Angiography. JAMA Netw Open. 2020;3(7):e2011444. Available at: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2768616
(8) van Rosendael AR, Lin FY, van den Hoogen IJ, Ma X, Gianni U, Al Hussein Alawamlh O, Al'Aref SJ, Peña JM, Andreini D, Budoff MJ, Cademartiri F, Chinnaiyan K, Choi JH, Conte E, Marques H, de Araújo Gonçalves P, Gottlieb I, Hadamitzky M, Leipsic J, Maffei E, Pontone G, Raff GL, Shin S, Kim YJ, Lee BK, Chun EJ, Sung JM, Lee SE, Han D, Berman DS, Virmani R, Samady H, Stone P, Narula J, Bax JJ, Shaw LJ, Min JK, Chang HJ. Progression of whole-heart Atherosclerosis by coronary CT and major adverse cardiovascular events. J Cardiovasc Comput Tomogr. 2021;15(4):322–30. Available at: http://journalofcardiovascularct.com/article/S1934-5925(20)30505-0/abstract
Technical Terms
Ketogenic diet: A ketogenic (or ‘keto’) diet is a low-carb, high-fat way of eating that puts your body into a state called ketosis, where it burns fat for energy instead of sugar from carbs. People on keto usually predominantly eat foods like meat, cheese, eggs, and oils, while avoiding bread, pasta, fruit, and most sweets. This diet has been shown to be effective for certain clinical conditions such as drug-resistant epilepsy, but robust benefits for other conditions are less well evidenced.
Carnivore diet: The carnivore diet is an extreme version of low-carbohydrate eating where you only eat animal-based foods—mostly meat, eggs, and sometimes dairy. It completely cuts out plants, including fruits, vegetables, grains, and nuts.
LDL cholesterol: LDL stands for ‘low-density lipoprotein’, and it is commonly called ‘bad cholesterol’ because high levels cause heart disease. The LDL particle itself carries cholesterol through your blood and can get ‘stuck’ inside the artery wall and cause plaque to build up (especially if levels are high).
Median: The median is a way to find the middle value in a set of numbers. If you lined up all the numbers from smallest to biggest, the median is the one in the center. For example, the median value of the following set of numbers is 5: 1, 2, 3, 4, 5, 6, 7, 8, 9. If data are normally distributed, the median and the mean (or average) are equivalent. When data are skewed, and/or when there are extreme outliers in a dataset, the median is a better measure than the mean to describe the distribution of a dataset because it is not influenced by extreme values.