I have previously posted on this topic several times over the past few years – you can read my prior posts by clicking here, here, and here. Having mentioned his film and the screening it will be having in the area (April 13th at the AMC 11 in Dartmouth – click here if you’d like to reserve tickets), I’d like now to come back to this research and discuss my latest thoughts on it.
First off, if you don’t want to read my prior posts, the issue is as follows: we know that low-carb/keto diets work extremely well for many people, and often lead to huge improvements in numerous metrics that should LOWER the risk for cardiovascular disease. These include improvements in glucose levels, insulin levels, levels of HDL (“good”) cholesterol, triglycerides, blood pressure, inflammatory markers, body weight, and visceral fat. Against that, some (though in fact not most) people who go low-carb will experience a big rise in their LDL cholesterol, the type of cholesterol that is thought to INCREASE the risk of cardiovascular disease.
Please note that I’m not saying that low-carb/keto diets are the only or even the best way to lose weight and improve health. I’m simply acknowledging there is a fairly large subset of the population that seems to have better results with this type of diet than with the alternatives. Moreover, there is emerging evidence that some people with serious medical conditions get huge, particular, benefits out of being keto. For example, Chris Palmer, a psychiatrist at Harvard, has done research showing that some patients with severe psychiatric illnesses such as schizophrenia or bipolar disorder can be put into remission with a keto diet. Other patients with chronic inflammatory disorders such as rheumatoid arthritis or Crohn’s disease have experienced the same thing.
So the question becomes this: if you go keto and experience dramatic health improvements – whether that’s “merely” a reduction in things like your weight, blood glucose, and blood pressure, or the remission of a serious chronic illness – but your LDL cholesterol goes through the roof, what should you do? Are you at higher risk for cardiovascular disease? Or do the other improvements more than offset the rise in LDL, such that the diet on the net is reducing your risk for cardiovascular disease? Or is it even possible that in the state of being in ketosis – which is metabolically much different from the state most people live in – the risk of high LDL goes away almost entirely?
Unfortunately, conventional medicine has not displayed a lot of interest in the above questions, largely sticking to the message that high LDL is bad, period, and therefore anybody who experiences a rise in cholesterol on a keto diet should stop the diet, or at least pair it with a cholesterol lowering medication such as a statin.
This is where engineer Dave Feldman comes into the story. After adopting a keto diet to treat his own pre-diabetes, he developed astronomically high LDL cholesterol of the type not normally seen outside of rare genetic disorders. Rather than panic and go off the diet, he decided to investigate the matter, and he’s published quite a bit of interesting research on the topic over the past few years.
The nuance of the discussion surrounding all of the above issues is quite complicated, so if you are interested in learning more, I’d suggest coming to see the film (which documents Dave’s journey), or at least finding an interview with Dave Feldman on a podcast or on youtube.
And this is where I want to pick up today’s blog post. The most interesting experiment Dave has done so far regarding this topic is the “Keto-CTA Study.” In this study, which I have discussed a bit in my prior posts, he found 100 lean, metabolically, healthy people who had been on the keto diet for an average of about five years, and had every good marker of metabolic health (low glucose, high HDL cholesterol, etc) except for having sky high LDL (over 500 in some cases! For reference, many cardiologists start to get nervous about anything over 100).
Dave has coined the term “Lean Mass Hyperresponder” for these folks, and he’s been following them with serial CTA scans (a type of CT scan that can detect even very small amounts of plaque in the coronary arteries) to see if they do or do not develop atherosclerosis rapidly, as would be predicted from their high LDL cholesterol.
In my post from about a year ago, I discussed how a paper Dave’s group published in April, 2025, did show many of these people with rapid plaque progression, which seemed to have answered the question in a very negative way – in other words it suggested that yes, if you’re cholesterol goes up on a keto diet, that is a bad thing and puts you at high risk for cardiovascular disease.
However, there’s an update to this: the scans have since been re-analyzed using three different methods, none of which corroborated the original finding of rapid plaque progression. In other words, it now appears that the original concerning data may have been due to a technical glitch in the computer software that was doing the analysis, and there is hope that this group of patients might indeed be at low risk for heart disease after all.
The story is still very much unfolding, with much future research planned. For now my position remains that if you are able to achieve your health goals in a way that does NOT raise your LDL cholesterol to concerning levels (e.g. with a non-keto diet, or if you are one of the many people on keto who do NOT experience a rise in LDL with keto) then that is ideal.
However, if you’ve had amazing results with keto, but have experienced a big rise in LDL as a result, you can take some comfort from the research Dave has produced thus far.
