A new study presented at the American College of Cardiology’s annual meeting, ACC.23 Together with the World Congress of Cardiology, raised fresh concerns about cardiovascular-related drawbacks of popular ketogenic- or “keto”-style diets.
The keto diet has gained popularity in recent years for its ability to help people lose weight over the short term. Yet even people on less strict versions of the high-fat, low carbohydrate diet were more than twice as likely to suffer from a major cardiovascular event than those on a “standard” diet, the study’s authors observed.
Specifically, the authors looked at outcomes over an average of 11.8 years for 305 people who self-reported that their diets met the authors’ criteria for a “keto-like” low-carbohydrate, high-fat diet: no more than 25% of their total daily calories came from carbohydrates, and more than 45% came from fat. These participants were matched by age and sex with 1,220 people who reported following a “standard” diet. The average BMIs of the two groups were also similar.
Ultimately, 9.8% of those on a keto diet or keto-like diet experienced a new cardiac event such as blockages in the arteries that required a stent, a heart attack, stroke or peripheral arterial disease. Such events were seen in 4.3% of patients on a standard diet.
“Our study found that regular consumption of a self-reported diet low in carbohydrates and high in fat was associated with increased levels of LDL cholesterol— or ‘bad’ cholesterol—and a higher risk of heart disease,” lead author Iulia Iatan, MD, PhD, attending physician-scientist at the Healthy Heart Program Prevention Clinic, St. Paul’s Hospital and University of British Columbia’s Centre for Heart Lung Innovation in Vancouver, Canada, said in an ACC statement about the study.
While previous studies had already shown links between keto-like diets and higher LDL cholesterol levels—which are a known risk factor for heart disease—the ACC study is the first of its kind to examine the actual cardiovascular outcomes of participants.
The study’s authors noted that not everyone responds the same to the keto diet, with some people actually experiencing a decrease in LDL cholesterol levels when following the diet.
“One of our next steps will be to try to identify specific characteristics or genetic markers that can predict how someone will respond to this type of diet,” Iatan said.
Read the full statement about the study here.