A study finds that following the keto diet may increase the risk of fatal cardiovascular disease.
The low-carb diet has become incredibly popular in recent years as a powerful weight-loss tool, with an estimated 13 million Americans following it.
But Canadian researchers who tracked 1,500 people for more than a decade found that the diet may raise levels of “bad” cholesterol.
They found that those who followed a high-fat, low-carb diet were more likely to suffer from cardiovascular diseases such as clogged arteries, heart attacks and strokes, compared to their peers.
The team believes that this is because high levels of harmful cholesterol cause fatty deposits to build up in the walls of the arteries, which can narrow or block them.
“Among the participants on a low-calorie, high-fat diet [similar to the keto diet], we found that those with the highest levels of LDL cholesterol had the lowest levels,” said Dr. High-density lipoprotein (LDL) are the most at risk of cardiovascular disease.Our findings suggest that people considering following a similar diet should be aware that doing so may lead to increased levels of LDL cholesterol.Before starting this dietary pattern, “They should consult their health care provider. While on the diet, it is recommended that they monitor their cholesterol levels and should try to address other risk factors for heart disease or stroke, such as diabetes, high blood pressure, physical inactivity and smoking.”
However, a major limitation of the 12-year study is that the participants were only asked about their diets once. There was no way to check if they had adhered to the same diet all those years.
Our bodies naturally produce “bad” cholesterol, or low-density lipoprotein (LDL), but eating diets high in saturated and trans fats causes the body to produce more LDL.
LDL contributes to the buildup of inflammatory fatty deposits known as plaques in your arteries, which increases your risk of heart attack or stroke. It is one of two types of cholesterol in the body. The other – high-density lipoprotein (HDL) – absorbs cholesterol in the arteries and carries it back to the liver, then flushes it out of the body. That’s why it’s called the “good” cholesterol.
The keto diet involves getting between 60 and 80 percent of your daily calories from fats, including cheese, avocados and fatty fish, and 20 to 30 percent from proteins.
Followers try to consume as few carbohydrates as possible, which means cutting back on bread, rice and potatoes, among other sources. Carbohydrates are the main source of energy that the body uses when exercising or moving on a daily basis.
But the lack of carbohydrates in the body pushes people into a state called “ketosis” where it starts breaking down fats for energy. The idea is to tap into stubborn fat stores, speed up weight loss and help with mental clarity — although there are mixed results on how effective this is.
In the study, which was led by scientists at the University of British Columbia in Vancouver, researchers scanned a UK biobank for participants who followed a keto diet.
After looking at 70,684 people who had data on their daily calories and cholesterol levels taken at once, they found 305 participants who followed a keto-like diet.
This was defined as getting more than 45% of your daily calories from fat and less than a quarter from carbohydrates.
They were matched with 1,220 individuals whose diets did not meet this definition.
Overall, about three-quarters of the participants were female, with an average age of 54. They were all considered to be overweight.
Data were analyzed with controls for factors including diabetes, high blood pressure, smoking and obesity.
During the 12-year study, about 9.8% of people in the ketogenic diet group experienced a serious cardiac event.
This included heart attacks, strokes, and artery blockages that required a stent procedure – an operation in which a coil of wire mesh is inserted into an artery to prop it up and keep it open.
For comparison, in the group eating the standard diet, only 4.3% experienced serious heart events over the same period.
The researchers also found higher levels of low-density lipoprotein cholesterol — or bad cholesterol — and apolipoprotein B, a protein that helps carry fat and cholesterol through the body, in the keto group.
The study’s limitations include that participants were only tested on their diets once, meaning they may not have stuck to them throughout the 12-year study period.
The study was presented at the American College of Cardiology’s Annual Scientific Session as well as the World Congress of Cargiology in New Orleans, Louisiana.