Very Concerning Article Claiming Keto Diet Causing Afib in Rats and Humans



When you say that, I assume you’re referring the edge on say a steak that almost nobody ever eats ( I’ve never known anybody that does at least) and not the marbled in stuff that melts in your mouth?


Any visible fat. When my husband has a steak, all that is left is a chewed up bone that does not have enough meat on it for our dogs (you should never give dogs cooked bones). My leftover steak could feed a pack of wolves! I cut out anything that is visible fat, whether on the end or in the middle. My favorite cuts are marinated skirt steak or filet mignon. I will eat strip steak or prime rib but not my first choice


@CFLBob @ctviggen @lfod14 Thank you for the comments. I absolutely agree that the commercials for Afib are just that but when I see a 40 year old former WNBA player hawking the meds it does give me pause. It sounds like a huge PITA in terms of limiting your lifestyle and of course health and mortality risk. I really would just hate to put effort into fasting only to find I was doing harm.

@CFLBob when you say you were low carb when you had the cardiac episodes, do you think it was simply not enough to make you healthier? Do you feel like you have derived additional benefits from Keto and that made most of the episodes go away? Is it possible it was a freak thing from something unrelated? I have had weird things over the years (not cardiac), they happen, last a little while, I ignore them and they go away eventually. I will do some experiments to see if it helps and am always grateful if I do not need conventional medicine as I do not trust doctors. I do not find them particularly helpful at any rate.

Your mentioning low carb is always an issue for me because while I have attempted to be low carb and keto for almost the last 4 years, I am generally not in Ketosis unless I am fasting (it was a weird consolation when I first read the article!) Some of it is doing lazy keto, and some is that I do not seem to produce breath ketones and I am too cheap to buy a blood monitor. I am definitely fat adapted as last week I forgot to eat for 24 hours except for coffee with cream.

Here is an interesting discussion of Magnesium Orotate

(May the blessing of bacon be always with you) #24

Well, you do now! Yum! :yum:

(Michael - When reality fails to meet expectations, the problem is not reality.) #25

Ditto. Even before keto I never left fat on my plate. :yum::yum:

(Central Florida Bob ) #26

That’s a tough question. It seems to me to have been a freak thing because I’ve never had a repeat of the nearly two weeks of constant pulse rhythm oddities. I’ve never had any more than an hour or two of those feelings since then, and not even once a year. Still, that’s not completely gone.

When I had that couple of weeks of weird heartbeats in '13, I was more or less eating the Zone diet. I think I’d gone down from 40-30-30 (%calories of carb-protein-fat) to maybe half the amount of carbs, but still more than keto. I eventually went keto because I kept gaining weight, even counting calories and reducing carbs, not for the cardiac thing.

The first time I saw the cardiologist he said something like, “sometimes these arrhythmia events just happen and we never know why, but most of the time we do know why”

About not producing breath ketones, “they say” that the longer you’ve been keto, the less your body wastes them. I have one of those cheap breathalyzers now as the only way I ever check ketones. It’s virtually always close to .05 no matter what I do. I never see high numbers, fasting and exercising, anything. Well, eating a lot of fat might make them go up.


Thanks for posting this @Saphire.

I wonder if Tom @tdseest still looks in on the forums? He is a lived expert on heart arrhythmias and the ketogenic diet.

I need to find a reference for you as to why rats are not a good animal for ketogenic diet studies. I think it was well explained on either the STEM talk podcast, or the Peak Nutrition podcast. So, the rat studies needs to be ‘triangulated’ with other data sources, such as mechanistic studies where beta-hydroxy-butyrate is tested on human heart cell cultures, and other animal models for human disease, possibly a primate study would be more clear. It may be worth gathering other experimental types to fill out the picture?

It’s interesting that you relate the concern to viral disease. Can I say SarsCov2? There definitely are ACE2 cell receptors concentrated in heart muscle tissue. Those cells can then be very badly impacted from COVID-19. So correlating the two concerns is a worthy discussion.

I hope Tom is around to comment.

Oh, I had a bout of AF on Wednesday night just passed. 2am.I treated it at home with therapeutic steps that I have worked out that work for me. I flipped i back to normal rhythm within an hour this time. I do have a beta-blocker on hand if I need it, but that is rarely. My n=1 observation is that I developed atrial fibrillation in 2017, 3 years after starting ketogenic eating. The first episode related to going off the plan. After a bit of research and self-experimentation I solved the problem for my own situation, including reverse remodelling my heart and resolving left atrial enlargement. All that on a ketogenic diet. But since I have been doing some carnivore challenges the AF episodes do reoccur. For me zero carb carnivore is not as ketogenic as the standard ketogenic diet.


Thank you,

I wish that were true but it has been this way since about 4 months into Keto back in 2017. Except When I am binging (sadly happens to often) I am nowhere near Zone levels. In a binge I am at SAD levels of carbs. However I think when I am trying to stay keto It is more that since I do not love fatty meats, I tend to eat nuts, some lower carb fruits like berries and more almond flour than I should. All block ketosis since I am not active. I am ok with that. I know when I am in ketosis because I get a certain taste and feel the tiniest bit nauseous. It is subtle but I know it is there.

Actually this concern way predates Covid. I posted a long time ago, in 2017 or 2018 that shortly after starting fasting and then Keto I started getting a lot of colds. They were mostly an annoyance. I could not figure out why and then someone posted an article, possibly @richard that fasting made you more vulnerable to viruses and less vulnerable to bacteria (since I got a bacterial infection in the middle of a fast in 2017 or 2018 I am not sure that is true for me).

The viruses seemed to stop in July 2018, not sure if it was because I started taking Lypisomal Vitamin C or because I did not fast as often. Did not have another illness until after Thanksgiving 2019 where I both cheated alot and was around a lot of people. It was a whopper, it was so bad I later thought it was an early version of Covid but since I had no antibodies, it was not. Bottom line, I am willing to risk an ordinary cold by fasting but not Covid which is why I have limited myself to 36 hour fasts or less as it is usually on Day 3 that I start to get sick (not that it always happened).

As for rats, I might have dismissed it the same way cholesterol in rabbits is dismissed but the link to the earlier study on patients with subsequent Afib had higher levels of circulating BHB made me very nervous

(Edith) #29

I will have my keto and/or carnivore four year anniversary this June. In all that time, I’ve only been sick once, and that was about a month after I was in a car accident. I think the stress of the car accident lowered my resistance. I do not fast except for some intermittent fasting every once in a while. Maybe your body finds fasting stressful.

(Bob M) #30

Not a big deal. After 7+ years low carb/keto, my breath ketones are between 20-30 normally (ketonix, first edition), whereas they could get into the 80s years ago.

@CFLBob The ONLY time my breath ketones go up (save fasting multiple days) is when I eat a lot of fat.

For comparison (when I was testing “resistant starch”):

(Bob M) #31

Sorry, did not read this until now. This is completely incorrect. As someone with heart failure, ketones are the preferred fuel for the failing heart:

Lots of studies here, but here’s one:

When blood sugar remains at 100 or higher
(Michael - When reality fails to meet expectations, the problem is not reality.) #32

That has been my understanding as well. However, from the article cited I find this ‘takeaway’ curious:


These results suggest that ketogenic diets do not enhance cardiac ketone body metabolism, but rather stimulates fatty acid oxidation, which may be responsible for the improved cardiac remodeling and performance.

From the original paper, which is the source of the above ‘takeaway’ I presume:


… Diets with higher fat content, but enough carbohydrate to limit ketosis, also improved heart failure, while direct ketone body provisioning provided only minor improvements in cardiac remodeling in CS-MPC2−/− mice…

Unfortunately, the paper is behind a subscription/pay wall so only the abstract is viewable. Maybe I’m missing something, but it seems like they downplay the role of ketones and say that metabolism of straight fatty acids causes the improvement.

When blood sugar remains at 100 or higher
(Bob M) #33

Yeah, I can’t get it, so I’m not totally sure what that means. They did inject mice (if you look way at the bottom of the page, they have “extended data”, where they describe the injections) with BHB. Or here:

But it doesn’t say under what conditions.

When I was originally looking into this, I got a bunch of studies. Here’s another:

Now, I THINK this should transfer to “normal” hearts, but it’s hard to say that it does.

When blood sugar remains at 100 or higher

i realized i posted in the wrong place. :smiley:

(Scott) #35

This nobody eats all the fat on a steak. I also select cuts based on the amount of fat they have, the more the better.

(Vic) #36

I eat it first, its the best part. Yummm

(Bob M) #37

Here’s a good article that just came out about ketones and the heart:

My least favorite part:

The KD has become extremely popular, both within and outside of the medical arena. KD consists of a very low-carbohydrate and high-fat diet that forces the body into endogenous ketosis (25). Although sustained KD can raise blood βOHB to 2 to 4 mmol/l (10), long-term compliance is low, often due to gastrointestinal (GI) distress.

(Michael - When reality fails to meet expectations, the problem is not reality.) #38


Thanks for the link, Bob! Basically, the criticism seems to be: “Wow, ketones are really beneficial to heart health and wellbeing. Too bad you have to give up ice cream, pizza and [add your fav carb here] because no ones gonna do that. Oh! by the by, we can just add exogenous ketones to SAD and we’re all good.”

I find it hilarious when folks who don’t eat keto express their disbelief that anyone can eat keto ‘long term’. Which means a day longer than their experiment lasted.

(Gregory - You can teach an old dog new tricks.) #39

More like lack of donuts distress … :grin:

(May the blessing of bacon be always with you) #40

Yeah, I guess four years is very short-term.

Surprisingly, given that glazed doughnuts were my carb of choice, I don’t really miss them. What I miss is bread. Go figure!