Keto-Like Diet Could Raise Heart Disease Risk

A new study found that people on a keto-like low-carbohydrate, high-fat diet had more than double the risk of major cardiovascular events than people who didn’t follow a keto-like diet pattern.

The ketogenic (keto) diet is a high-fat, low-carbohydrate diet designed to shift the body's metabolism from using glucose as the primary energy source to using ketones produced from stored fat.

This popular dietary pattern typically involves reducing carbohydrate consumption to less than 50 grams daily and increasing fat intake to about 60% to 80% of daily calories. Conversely, protein intake is moderate — about 20% to 30% of daily calories.

According to some research, along with weight loss, the keto diet may help lower blood sugar, improve insulin sensitivity, and provide other health benefits.

However, new research presented on March 5 at the American College of Cardiology’s Annual Scientific Session and the World Congress of Cardiology raises questions about the true health impact of this new diet craze.

The study examined 305 participants from the U.K. Biobank who reported following a low-carbohydrate, high-fat (LCHF) diet and compared them with 1,200 people who reported eating a standard diet. The participants completed the dietary questionnaires over 24 hours.

Using cholesterol blood tests obtained at the time of recruitment, the team found that participants following the keto-like diet had higher low-density lipoprotein (LDL) and apolipoprotein B (apoB) levels than those eating a standard diet.

ApoB is a primary protein component found in LDL and other lipoprotein particles that may be a predictor of cardiovascular disease risk. Moreover, high LDL levels are associated with increased heart disease and stroke risk.

In addition, after a follow-up averaging 11.8 years, the scientists found that 9.8% of participants who consumed the keto-like diet experienced a new cardiovascular event, such as a heart attack, stroke, or artery blockages, versus 4.3% of those eating a standard diet.

In a news release, lead author Iulia Iatan, M.D., Ph.D., notes, "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."

"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 health care 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," latan explains.

Despite the findings, the study had some limitations. For example, because the participants self-reported their dietary data and the data came from one point, the reports could be inaccurate and provide only a snapshot of their food intake.

Moreover, the scientists say that not everyone responds the same to the LCHF diet.

In addition, although the data showed an association between the LCHF diet and cardiovascular disease risk, because the study was observational, it does not prove a keto-like diet causes an increased risk of cardiovascular events.