Inaccurate news stories suggest low carb causes atrial fibrillation

I tried to ignore it, but I just can’t anymore. The misinformation being publicly touted needs clarification.
Popular news articles are covering an observational study linking “low-carb” diets to atrial fibrillation, a potentially dangerous heart-rhythm disorder.
NBC News: Study: Low-carb diet could lead to AFib
EurekAlert: Low-carb diet tied to common heart rhythm disorder
For starters, this study is not published yet, and it hasn’t even been presented at a scientific meeting. It looks like it will be presented next week at the American College of Cardiology’s annual meeting. Scientific integrity, but apparently not journalistic integrity, dictates that one should not discuss the details of a study until it is published. The reasons for this are clear, one of which is that we may draw false conclusions without having the actual data available to review.
This study is a perfect example. The headlines state this study determined those who ate a “low carb” diet were at higher risk of developing atrial fibrillation. Once again, however, the definition of low carb was less than 40% of calories from carbohydrate. That’s 200 grams on a 2,000-calorie diet. I have seen responses on social media such as, “I eat fewer carbs than that on my biggest cheat days!”
While 40% may be low carb by Standard American Diet (SAD) standards, it is a far cry from the less than 50 or even 20 grams of carbs to which most low-carb eaters adhere. There is a reason for the differentiation. At 40% carbs, our bodies are still burning carbs and glucose for fuel. So what happens to the fat? It gets stored. Or worse, it gets oxidized and stored. Either way, the combined high-carb and high-fat diet is the one that is most prone for health problems.
But the problems with the study don’t stop there. This is the same poor quality of evidence that we point out time and time again. Observational trials can suggest an association, but do not prove causation. The food frequency questionnaires used to record participants’ diets are notoriously inaccurate at capturing what people really eat, and they miss dietary changes that happen after the questionnaire was completed. Last, there are numerous potential confounding variables. Did people decrease their carb intake from very high to slightly high (from more than 60% to less than 40%) because they were obese and wanted to lose weight? Did they have diabetes or hypertension and wanted to improve them?
Obesity, sleep apnea, hypertension and diabetes are all risk factors for atrial fibrillation. It turns out that a low-carb diet (the real low carb diet, not the fake one in this study) improves obesity, sleep apnea, hypertension and diabetes. It’s my guess that a higher-quality, better designed study would likely show that low-carb nutrition prevents atrial fibrillation. That’s what I see in my practice, and that is how I am going to continue to use low-carb nutrition. When followed correctly, low-carb nutrition is as a powerful tool to improve health.
Thanks for reading,
Bret Scher, MD FACC


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- Beverly YinglingKudos to you & your family, Autumn!! You all have taken the first step in your journey together!! I am sending positive thoughts your way. As Kristine said in her post. Each person has to find the right balance of food groups, nutrients,etc for his/her body. Good luck to you & your family!!
- Shannon ColdironAre body is made of carbon and carbohydrates are easily converted into energy provided it is from our species specific food which of course is Fresh Fruits and we can balance it out if needed with Raw leafy greens. I feel better than every since cutting out grains, oils, and salt. I now consume 70 to 80 % of my (4000 to 5000) daily calories as fresh fruit and the rest is made raw vegetables. I am leaner than ever and actually building muscle
- 1 comment removed
- Stephen CarrierI almost died from A fib, when I was doing Atkins my heart would be jumping in my chest like it wanted to fly out, if I ate some carbs/ sugar the rythm would return to normal, 7 cardio versions, and, 3 ablation later, Dr. Fischel stopped it. S,Carrier
- Beverly YinglingI stand corrected
- Beverly YinglingAgreed. And again the key words here are "balance", " low carb" ( as opposed to no carb). and "individual needs".
- Jeanfree book? the book is not free it is sold on amazon
- EricKeep drinking the kool-aid and spouting off rhetoric from low carb sites. Most people do great with carbohydrates included as a balanced part.
The common thread with all these comments seem to be a defined change in A1C, weight loss, and better health markers. That is great, if it works for you!
However , it’s unfair to discount all the normal individuals (not biased members of low carb sites) that function well and maintain normal BMI and health markers on SAD.Just because she is a personal trainer doesn’t discount her recommendations of following a balanced diet. She actually is in line with the science , unlike your personal anectodotes of the efficacy of LCHF.
Healthy people don’t need A1C test or suffer from the ailments aforementioned in previous comments . If a subject is eating a Carb inclusive diet and maintaining normal weight levels, it’s dogmatic to believe that a LCHF diet will improve their life.
Summary: Removal of one category of food is likely to reduce overall calories in subjects who are overweight, thereby leading to improved health markers.
FWIW I also think the study is flawed, like most studies.
- 4 comments removed
- LeahYes
- RickI have Afib and flutter tendencies brought on by scarring in the pericardium.
Heart has nowhere to beat but up basically, so the electrical paths are disrupted.I was in moderate keto for most of 2018.
my flecainide (for flutter) was 50mg b/d
I had no afib or flutter, except the odd breakthrough
No booze, little in the way of sweet stuff and feeling great.Christmas day I ate the big meal, drank the grog and was off to hospital christmas night
with AF and flutter.Docs upped the flec to 100mg b/d and metoprolol for the Afib.
Damn near killed me. Metoprolol is very dangerous.It's ten months since then and I still haven't recovered.
Not been eating keto since then apart from half hearted attempts - no real energy or discipline till now.I managed to will the Afib away after ditching the metoprolol (read Wayne Dyers book about believing it, and then seeing it)
No idea how, but it worked.But the flutter remains, often when I exercise I have to add another 50 mg flec 15 minutes before I start, just to stop
falling in to flutter afterwards. Works most of the time.SO I am trying out the carnivore diet, with added fat so I can stay in ketosis.
Hoping I can kickstart things again and get back to 50 mg b/d and regain some energy.Also working through the Heartmath Institute material, plus using their Inner Balance phone app.
Some have reported cessation of arrythmias after 6 months or so.Keto worked for me, but falling off the wagon was disastrous.
- JerrilynnLinda, did you have paroxysmal a-fib (attacks of tachycardia) or asymptomatic a-fib (continual irregular heartbeat.
- HeatherThank you for this article! I have cold-induced paroxysmal a-fib and I just started keto. I really didn't want to stop since I have seen such great results in 2 weeks. Again, thank you!
- JeremiahI'm not a doctor (so if you have afib and want to do keto, please consult with your doctor first), but I do have afib, and not only do carbs increase such, but true low carb -at least keto anyway (for me never more than 30g of carbs/day), is consequently actually the most effective thing I've found for eliminating such -right, the exact opposite of increasing such -and right, eliminating -not reducing. I only get afib when I break my diet and consume too many carbs, and when maintaining my diet (which is also low to moderate protein -which may play a factor ??) I don't have afib -I honestly think that if I keep up with keto, and stop cheat days that such will literally cure my afib -or at least I won't ever have it anyway -since I never get it when I'm on this diet...food for thought (no pun intended), but we'll see how it goes! 😊
- ColleenI'm late to the party but just started a low carb diet with my husband. I'm 73 and have been on BP meds for at least 15 years. I take Atenolol 50mg 2xdaily and Amlodipine 5mg at night. I've been on the low carb diet for a week and have had typical symptoms of changing my diet but nothing serious. However, tonight, about 3 hours after I took my 2nd Atenolol of the day, I started getting arrhythmia, which I haven't had for a long time. My carb intake is around 80g...maybe 90g. Should I talk to my doctor about checking the dosage? I think my BP dropped because I felt lightheaded and a little disoriented. Are my electrolytes needing a boost, also? Thank you
If you want to argue that some plants or the like that contain carbs are good for us to eat, that's one thing. But to say we "need" carbs is wrong. Completely wrong. Without scientific evidence.
I still eat vegetables because I like the taste of them, but I don't NEED to eat them. I've gone from eating a lot of vegetables to going days without ANY vegetables (or for that matter food).
Autumn, if you can, also avoid all seed oils, like canola, soybean, sunflower, etc. Another supposedly "healthy" item that's anything but.