Keto diets linked to high risk of heart disease: new study

Diets similar to the popular Keto diet may be linked to a higher risk of heart disease, new research has found.

The study, which has not been peer reviewed, was presented Sunday at the American College of Cardiology’s Annual Scientific Session Together With the World Congress of Cardiology.

The findings showed that people on n low-carb, high-fat (LCHF) diet — similar to the Ketogenic diet — had more than two times higher risk of having several major cardiovascular complications.

This comes as approximately one in five Americans report being on a low-carb, keto-like or full keto diet.

Researchers compared the diets of 305 people on LCHF diets as well as about 1,200 people eating a standard diet with more balanced eating habits.

The team defined an LCHF diet as consisting of 45% of total daily calories coming from fat and 25% coming from carbohydrates.


A ketogenic meal laid out on a dining table
Low-carb, high-fat (LCHF) diets, similar to the Keto diet, have become increasingly popular in recent years.
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The information analyzed in the study was taken from the United Kingdom database UK Biobank, which followed people for at least a decade. They also noted that 73% of their participants were women with an average age of 54 years old and average body mass index (BMI) of 27.7- those on the standard diet had an average BMI of 26.7.

After about 11.8 years and even when adjusted for other risk factors, the research showed a much higher risk of developing cardiovascular conditions.

The study concluded that people on the LCHF diet had higher levels of low-density lipoprotein (LDL) cholesterol — sometimes known as “bad” cholesterol — and apolipoprotein B, a protein that coats LDL cholesterol and can predict heart disease.

The researchers also found that those consuming an LCHF diet had a total fat intake higher in saturated fat and double the consumption of animal sources (33%) compared to those on the standard diet (16%).


Aching heart and heart attack, adult male
Heart disease is the leading cause of death for both men and women in the United States killing about 697,000 Americans in 2020, according to the CDC.
Getty Images/iStockphoto

“Among the participants on an LCHF diet, we found that those with the highest levels of LDL cholesterol were at the highest risk for a cardiovascular event,” lead author, Iulia Iatan, MD, Ph.D., attending physician-scientist at the Healthy Heart Program Prevention Clinic, St. Paul’s Hospital said in the press release.

“Our findings suggest that people who are considering going on an LCHF diet should be aware that doing so could lead to an increase in their levels of LDL cholesterol. Before starting this dietary pattern, they should consult a healthcare provider. While on the diet, it is recommended they have their cholesterol levels monitored and should try to address other risk factors for heart disease or stroke, such as diabetes, high blood pressure, physical inactivity and smoking.”


People on LCHF diets were found to have higher levels of "bad" cholesterol compared to those on a standard well-balanced diet.
People on LCHF diets were found to have higher levels of “bad” cholesterol compared to those on a standard well-balanced diet.
Getty Images/iStockphoto

However, the experts did note that not everyone’s body responded to the LCHF diet in the same way and called for more research to be conducted.

The Keto diet — generally suggested as being 10% carbohydrates, 20% to 30% protein and 60% to 80% fat — and similar LCHF diets have become increasingly popular in recent years as a quick way to shed weight.

But experts have previously warned that it may have some longer-term adverse effects in the heart and even the so-called “Keto crotch.”

The restrictive diet works by providing the body with limited carbohydrates forcing the body to break down fat to create energy instead. The breakdown of the fat then produces ketones, chemicals that the body uses as energy in the absence of carbohydrates.

Experts warn that these LCHF diets eliminate other healthy and necessary food groups like fruits, legumes and whole grains and may not be the best option for everyone — although it has been found to help control seizures for children with epilepsy.

The new findings “can only show an association between the diet and an increased risk for major cardiac events, not a causal relationship,” researchers noted, but suggests more studies should be done.

Heart disease is the leading cause of death for both men and women in the United States, according to the Centers for Disease Control and Prevention.

The keto diet — which counts Gwyneth Paltrow, Halle Berry and Kim Kardashian as celebrity devotees — has also been found to be one of the worst for the environment. The diet was estimated to generate around 6.6 pounds of carbon dioxide for every 1,000 calories consumed.

While these fad diets may entice those trying to lose some weight fast, experts warn that they are not sufficient long-term solutions.

“Losing weight may seem like a daunting task, but in reality, it doesn’t have to be,” said Courtney McCormick, corporate dietitian at Nutrisystem.

“The best way to conquer your weight loss goals and overcome challenges is to find an affordable program that will help you every step of the way by providing things like real-time support, an intuitive app and meals that are portion-controlled, but protein-packed to help you stay fuller longer.”