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New research suggests that low-carb, high-fat diets like Keto may significantly raise your risk of cardiovascular issues such as heart attack, stroke, and blocked arteries. FG Trade/Getty Images
  • A new study has found a link between “keto-like” diets and higher cholesterol.
  • It was also associated with a greater risk for cardiovascular disease.
  • People eating a keto diet tended to eat more saturated fat.
  • Nutritionists say these findings are not surprising.
  • They suggest that people stop thinking of carbs as the enemy.

According to research presented on March 5, 2023, at the American College of Cardiology’s Annual Scientific Session Together With the World Congress of Cardiology, a “keto-like diet” was associated with negative effects, including higher levels of LDL cholesterol, the so-called “bad” cholesterol.

Additionally, it was linked with a greater than two-fold increase in the risk of cardiovascular (CV) issues — such as heart attack, stroke, and blocked arteries.

Keto diets are experiencing growing popularity with it being reported that 5% of people have tried a keto diet. It is estimated that the U.S. market for ketogenic diet products will reach a global value of $15.6 billion by the year 2027.

Previous research has found that keto diets are beneficial, at least in the short term, due to their ability to reduce blood pressure, triglycerides, and glycosylated hemoglobin (HbA1c), a marker for elevated blood sugar.

They are also associated with better levels of HDL, “good” cholesterol, and weight loss. However, the long-term effects of keto diets on CV risk are not known.

For the purposes of the study, a keto-like diet was defined as one that was low in carbohydrates (25% of calories) and high in fat (45% of calories).

The research team examined the diets of 305 people who were following this low-carb, high-fat (LCHF) diet, comparing them with 1,200 people who were eating a standard diet.

Health data on the participants were obtained from a large biomedical database called the UK Biobank.

Follow-up was done for, on average, about 11.8 years with adjustments being made for other heart disease risk factors, like smoking and hypertension.

Upon analysis of the data, it was found that people on the LCHF diet had greater levels of three predictors of cardiovascular risk: LDL, cholesterol, and apolipoprotein B.

The study authors further noted that these same individuals had more than double the risk of artery blockage, heart attack, stroke, and peripheral artery disease.

They also found that people eating an LCHF diet had a greater intake of saturated fat.

According to the American Heart Association, eating too much saturated fat can increase your risk for heart disease and stroke by raising cholesterol.

Samantha Coogan, program director, Didactic Program in Nutrition & Dietetics at the University of Nevada, Las Vegas, says these findings are “concerning, although not surprising.”

“One of the problems (and there are many) with keto is that there are very vague guidelines for how someone might adopt it, and most take it as ‘eat whatever type of fat you want, as long as it’s fat, with little to no carbs,'” she said.

Additionally, there is no real distinction made between “bad” fat, like saturated fat, and “good” fats like unsaturated fat and omega-3 fatty acids, said Coogan.

She further explained that high saturated fat foods — like beef, bacon, and butter — are often heavily promoted by proponents of the diet. For example, the creator of the popular “Bulletproof coffee” advocates putting butter in your morning cup of java.

Coogan said keto diets also tend to focus more on weight loss without taking into account heart health.

“Many true believers irresponsibly promoted ‘unlimited amounts of bacon,'” she said.

Sharon Palmer, registered dietitian, author, and blogger at The Plant-Powered Dietitian, agreed with Coogan that these findings were not surprising.

“Many nutrition experts and physicians have been concerned about this potential since keto diets gained in popularity, and they have been seeing cases of cardiovascular events associated with these diet patterns,” she said.

Palmer noted that keto diets tend to be severely restricted in whole plant foods, which we know to be protective of the heart, due to their fiber, mineral, vitamin, and phytochemical content. In addition, keto diets are often high in saturated fat, which raises cholesterol and clogs arteries.

“It’s a double whammy,” said Palmer. “People are restricting foods that help protect the heart, and filling up on foods that promote heart disease.”

“A better diet is one that is good for overall health for the long haul,” said Palmer, “not a quick-fix weight loss diet that, in the end, causes serious health risks.”

Specifically, this would be a diet that is more plant-based, she explained.

“Instead of restricting foods like fruits, whole grains, and pulses, they should be the center of your plate. Research actually shows more plant-based diets are linked with healthier body weights, said Palmer.

Coogan further pointed out that keto diets are often unsustainable for people because of the severe restriction of carbs. She advises that people don’t deprive themselves of what they crave as this will “get you every time.”

She suggests that people eat consistently throughout the day, which can keep their metabolism from slowing down.

“When we try to starve ourselves for long stretches is when our metabolism can start to slow down as a means to compensate for the uncertainty of when the body will be fed again,” she said.

Another thing she advises is eating an adequate balance of protein, fats, and carbs.

“Aim for 10-35% of calories coming from protein (higher end if you engage in more strength training), 20-30% of calories coming from fat, and 45-65% of calories coming from carbs (higher end if you’re an endurance athlete or trying to put on ‘bulk;’ lower end if trying to ‘lean’ out/reduce water weight),” she said.

She added, that “carbs are not the enemy.”

“The brain needs a minimum of 130 g per day just to function and even more for anything over and above waking up,” she said.