A new study found that eating a ketogenic diet may double your risk for heart disease. A low-carb, high-fat “keto-like” diet is linked to higher levels of “bad” cholesterol and may double the risk for cardiovascular events, such as blocked arteries, heart attacks and strokes.

“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— or ‘bad’ cholesterol-and high risk of heart disease,” said lead author Dr. Iulia Iatan, with the Healthy Heart Program Prevention Clinic, St. Paul’s Hospital and University of British Columbia’s Centre for Heart Lung Innovation in Vancouver, Canada, according to CNN.

The latest study points out that the harms of a ketogenic diet may outweigh the benefits, says Christopher Gardner, an expert in nutrition science and a professor of medicine at Stanford School of Medicine, who has been studying the effects of ketogenic diets for years but was not part of the latest research.

“Elevated LDL cholesterol should not be dismissed as simply a negligible side effect of a VLCD (very-low-calorie diet) or a ketogenic diet,” Gardner said, pointing out the higher risk of cardiovascular events in people with higher ketone levels in the blood, compared to those on a standard diet.

In the study, which was presented Sunday at the American College of Cardiology’s Annual Scientific Session with the World Congress of Cardiology, the researchers defined a low-carb, high-fat (LCHF) diet as 45% of total daily calories coming from fat and 25% coming from carbohydrates.

Iatan said that the rationale behind the study came from the number of patients she and her colleagues would see in their cardiovascular prevention clinic with severely high cholesterol who followed ketogenic diets.

“This led us to wonder about the relationship between these low-carb, high-fat diets, lipid levels, and cardiovascular disease,” she said, according to CNN. The results of the study came after analyzing data from a major UK Biobank study. The researchers compared 305 people following low-carbohydrate diets with 1,200 individuals on standard diets over 11.8 years. They found the risk of major cardiovascular events, including heart attack, stroke, and peripheral arterial disease more than doubled in the low-carb, high fat diet group. LDL (“bad”) cholesterol levels were also higher in the low-carb group.

The Physicians Committee for Responsible Medicine (PCRM) called for renewed warnings against low carbohydrate “ketogenic diets” amid the new findings.

“The bubble has burst on low-carbohydrate diets,” said Dr. Neal Barnard, president of PCRM. “Despite the risks of the cholesterol-laden ‘keto diet,’ many people try them in hopes of losing weight. What they lose is their heart health. We need stricter warnings about these fad diets.”

Low-carbohydrate diets have been popular for decades, starting with the Atkins Diet, the South Beach Diet, and, more recently, “ketogenic” diets. They greatly reduce healthy fruits, grains, beans, and other carbohydrate-containing foods, replacing them with meat and fats. Medical experts have warned of a variety of risks, including cardiovascular disease and cancer, in addition to weight regain after the diet ends.