New study: Keto reduces, not raises, cardiovascular risk

Does a ketogenic diet put people at higher risk of heart disease? Recent research suggests, in fact, the opposite is true. 

Patients on a keto diet may significantly reduce their risk of heart disease, while losing weight and improving blood sugar, blood pressure, and other metabolic markers.

The latest study to show this is a new small pilot study published in Metabolites. The research team, including keto weight loss expert Dr. Tro Kalayjian, partnered with a local manufacturing plant. They signed up interested employees with obesity and higher risk of cardiovascular disease to follow a weight loss and metabolic health program with carbohydrate reduction for six months.

The patients were taught how to eat keto and wore continuous glucose monitors and used ketone meters. They were supported by medical visits, Doctor Tro’s app, and had access to a health coach (including keto coach Amy Eiges, whose 230-pound weight loss success story we have previously shared).

Of the 10 patients who followed the program for six months, patients averaged a 44% reduction in their relative cardiovascular risk. Not only that, but the average weight loss was 38 pounds (17 kilos) and significant money was saved on prescription drug costs.

Metabolites: A company is only as healthy as its workers: A 6-month metabolic health management pilot program improves employee health and contributes to cost savings

While a small study, its findings align with the 1-year results of Virta Health, published in 2018. In that study, participants eating a keto diet and undergoing monitoring by their app-based program reduced their calculated cardiovascular risk by 12%. 

As a cardiologist, these results are important for me to share because they counter the outdated warning by many in mainstream medicine that keto diets are dangerous, may result in increased heart attacks, and may lead to premature death.

That warning, which runs counter to study results, denies a potentially beneficial intervention to millions of people. Instead, we need to recognize the value of well-formulated low carb diets for improving metabolic health, reversing type two diabetes, and improving calculated cardiac risk scores. 

As I explain in this new DDNews video, previous claims that keto increases cardiovascular risks are based on weak studies with multiple issues, including:

  • They study diets that are not in fact keto, defining low carb as under 40% of calories from carbohydrate, which means they contain up to 200 grams of carbs a day on a 2,000 calorie diet, which is more carbs than most people on a keto diet would eat in a week.
  • They are observational, relying on unreliable food frequency questionnaires and other weak forms of data collection.
  • They have other weaknesses of nutrition epidemiology, including healthy user bias and very low hazard ratios (meaning the risk is exceedingly small).

Granted, the new study by Dr. Tro and the Virta study do have their weaknesses as well. They are not randomized controlled trials and patients self-selected. And, in both cases, the study population was small. 

Another weakness is that the two studies don’t measure hard outcomes, meaning heart attacks or death. Researchers would need thousands of patients for a decade or more to report those findings. Instead, they report surrogate outcomes of a calculated score of cardiovascular risks.

But those are the same cardiovascular disease risk scores doctors use to decide whether a patient should start a cholesterol-lowering drug. The guidelines state anyone with a 10-year calculated risk above 7.5% should consider starting a statin. 

In Doctor Tro’s study, the average baseline risk of participants was 9.2%, squarely in the statin category. But after 6-months, the average risk reduced to 5.1%, no longer in the statin category. 

But the results don’t stop there. As noted, the study reported that the 10 patients lost an average of 38 pounds (17 kilos) and reduced their blood glucose, blood pressure, and prescription medications, leading to an annualized cost saving of $45,000 for just 10 people (more than $4,000 per person).

Getting healthier while saving money? That’s a win-win for patients, and for the manufacturing plant’s insurance plan that sponsored participants to help them get healthier.

So, the next time you hear that keto diets are bad for your heart, take heart in knowing these study results don’t support that statement. In fact, the opposite is likely true. 

Thanks for reading,

Dr. Bret Scher


Each week Dr. Scher creates two or three videos that review relevant or interesting scientific studies in the fields of nutrition, exercise, health, or disease and analyzes the researchers’ methods and findings. In doing so, he helps you better understand how to judge the quality of various research papers and make informed decisions about your own health and wellness. 

You can find more of Dr. Scher’s news videos on the Diet Doctor Youtube channel. Subscribe to the feed so that you don’t miss any of his videos. 

Or you can get more information about how to do a ketogenic diet to see if it is right for you.


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