Trendy zero carb Keto diet may double risk of heart disease, study warns

Following the Keto diet may raise the risk of heart disease and other deadly cardiovascular conditions, a study suggests.

The ultra-low-carb diet has become incredibly popular in recent years as a powerful weight-loss tool, with up to 13 million Americans estimated to be following it.

But Canadian researchers who tracked 1,500 people for over a decade warn that it may drive up levels of ‘bad’ cholesterol.

They found those following a high-fat, low-carb diet were twice as likely to suffer cardiovascular events such as blocked arteries, heart attacks and strokes than their peers.

The team believed that this was because they had higher levels of bad cholesterol, raising their risk of fatty deposits in artery walls that can narrow or block them.

Dr Iulia Iatan, a physician at the University of British Columbia’s Center for Heart Lung Innovation who led the study, said: ‘Among the participants on an low-calorie high-fat [Keto-like] 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.’

Eating a high-fat diet raises levels of low-density lipoprotein (LDL) cholesterol, which can build-up in deposits inside the walls of blood vessels.

This happens because receptors in the liver that help remove LDL cholesterol from the blood do not work as well. The American Heart Association also suggests that a higher fat diet leads to more LDL cholesterol being manufactured.

It can also raise levels of apolipoprotein B (apoB), which can help fat deposits to build up in the cells of arteries.

Not all cholesterol is bad, however. There is also high-density lipoprotein (HDL) cholesterol which absorbs other cholesterol from the blood and carries it back to the liver.

The Keto diet involves getting between 50 to 80 percent of daily calories from fats including brie, avocado and fatty fish, and 20 to 30 percent from proteins.

Followers avoid carbohydrates — found in breads, pasta, rice and potatoes among others — in order to induce starvation mode in the body.

The low carb consumption pushes the body into a state called ‘ketosis’, or starvation mode, where it starts to breakdown fats stored in the body.

This raises ketone levels, chemicals made by the liver in response to there being too little insulin in the body, indicating there is not enough sugar to meet energy needs.

This is thought to help speed up fat loss, give people better mental clarity and also reduce the risk of diabetes.

Celebrities like actress Halle Berry swear by the Keto diet and has been following it for more than 30 years to help manage her type 1 diabetes.

Legendary basketball player LeBron James also reportedly followed a version of the diet, when he just ate meat, fish, vegetables and fruits for 67 days back in 2014. He even turned down desserts made for him by a resort in Greece.

In the study, led by scientists at the University of British Columbia in Vancouver, researchers scanned the UK Biobank for participants who followed the Keto diet.

After finding 70,684 people who had data on daily calorie intake and cholesterol levels in their blood taken once, they checked found 305 participants who followed a ‘Keto-like’ diet.

This was defined as getting more than 45 percent of their daily calories from fats and less than a quarter from carbohydrates.

They were matched with 1,220 individuals whose diets did not meet this definition — and were described as ‘standard eaters’.

Overall, about three quarters of participants were female and they had an average age of 54 years. They were all also considered to be overweight. 

Data was analyzed, adjusting for factors including diabetes, high blood pressure, smoking and obesity.

During the 12-year study, about 9.8 percent of people in the Keto-like diet group suffered a serious cardiac event. 

This included heart attacks, strokes, and a blockage in the artery that needed a stenting procedure — an operation where a coil of wire mesh is inserted into an artery to support it and keep it open.

For comparison, in the group that ate the standard diet, only 4.3 percent faced serious cardiac events over the same period.

The researchers also found higher levels of LDL cholesterol — or bad cholesterol — and apolipoprotiein B, a protein helping to carry fat and cholesterol through the body in the Keto group. 

Limitations of the study include that participants were only quizzed on their diets once, meaning they may not have stuck to them throughout the 12-year study.

The study was presented at the American College of Cardiology’s Annual Scientific Session Together with the World Congress of Cargiology in New Orleans, Louisiana, on Sunday.