The ketogenic (or Keto) diet, which is low in carbohydrates and high in fat, may be associated with higher levels of “bad” cholesterol and a doubling of the risk of cardiovascular problems, such as blocked arteries, heart attacks and strokes. , according to new research.
“Our study found that regular consumption of a low-carb, high-fat diet was associated with increased levels of LDL cholesterol – or ‘bad’ cholesterol – and an increased risk of heart disease,” said study lead author Iulia Iatan of the Healthy Heart Program Prevention Clinic at St. Paul, and the Heart Lung Innovation Center at the University of British Columbia in Vancouver, Canada, in a statement.
“This study adds a lot to the scientific literature and suggests that the harms outweigh the benefits,” noted Christopher Gardner, a professor of medicine at the Stanford Prevention Research Center, who has conducted clinical trials on the ketogenic diet. Gardner was not involved in the study.
“Elevated LDL cholesterol should not be dismissed as a simple, insignificant side effect of a VLCD diet (very-low-calorie dietthat is, very low in calories) or ketogenic”, indicated Gardner, pointing to the greater risk of cardiovascular problems in individuals with higher levels of ketone bodies in the blood, when compared to those who follow a standard diet.
In the study, researchers defined a low-carb, high-fat (LCHF) diet. Low-Carb, High-Fat) as 45% of total daily calories from fat and 25% from carbohydrates. The study, which has not been peer-reviewed, was presented at the American College of Cardiology Annual Scientific Session in conjunction with the World Congress of Cardiology.
“The rationale for our study came from the fact that we see patients in our cardiovascular prevention clinic with severe hypercholesterolemia following this diet,” said Iatan during a presentation.
Hypercholesterolemia, or high cholesterol, increases the risk of heart attack or other adverse cardiovascular problems.
“This got us thinking about the relationship between these low-carb, high-fat diets, lipid levels and cardiovascular disease. Despite this, there is little data on this relationship,” he noted.
The researchers compared 305 people on a Keto diet with around 1,200 people on a standard diet, using health information from the British database Biobank UK, which followed people for at least a decade.
They also found that people following the LCHF diet had higher levels of low-density lipoprotein (bad cholesterol) and apolipoprotein B. Apolipoprotein B is a protein that coats the proteins in LDL cholesterol and may predict heart disease better than high levels. of LDL cholesterol.
The researchers also noted that people following a low-carb, high-fat diet consumed twice as much animal sources (33%) compared to those on a standard diet (16%).
“After an average of 11.8 years of follow-up – and adjusting for other risk factors for heart disease, such as diabetes, high blood pressure, obesity and smoking – people on an LCHF diet had twice the risk of having serious cardiovascular events. , such as coronary obstructions that had to be treated through coronary stent (angioplasty), heart attack, stroke and peripheral artery disease,” the investigators found, according to the released statement.
According to the researchers, this study “can only show an association between diet and increased risk of serious heart problems, not a causal relationship”, since it was an observational study, but their findings need further study. in-depth, “especially when nearly 1 in 5 Americans report eating a low-carb diet”.
Iatan noted that study limitations included measurement errors that occur when dietary assessments are self-reported, the study’s small sample size, and the fact that most participants were British and did not include other ethnic groups.
The study also looked at the longitudinal effect of following the diet. Most people tend to follow it intermittently for shorter periods.
Most of the participants – 73% – were women, which Iatan said was “quite interesting, but also supports the theory that women in general tend to follow more dietary patterns and are more interested in changing their lifestyles.”
When asked if there were any groups that weren’t harmed by following an LCHF diet, Iatan said that the length of time the diet lasts and whether or not weight is lost “can counteract the increase in LDL.”
“What’s important to remember is that each patient responds differently. And so there really is inter-individual variability in the response. What we found is that, on average, patients tend to increase their levels of ‘bad’ cholesterol”, he considered.
David Katz, a lifestyle medicine specialist who was not involved in the study, said, “There are many ways to go about an LCHF diet and it’s very unlikely that they all have the same effects on serum lipids or cardiac events.”
“The fact that an LCHF diet is associated with adverse effects comes as a shock to those who adopt these diets just because they are fashionable,” he added, however.
Most health experts point out that the keto fad, which banishes carbohydrates to make the body burn fat, eliminates healthy foods like fruit, legumes and whole grains. On the ketogenic diet, you limit your carbohydrate intake to just 20 to 50 per day – the lower the better. To get an idea, a medium banana or apple has about 27 carbohydrates.
“The food groups that have to be eliminated to achieve ketosis are the main sources of fiber in the diet, as well as many important nutrients, phytochemicals and antioxidants. This is of concern to many health professionals considering the VLCD or ketogenic diet harmful to health in the long run”, underlined Gardner.
Keto is short for ketosis, a metabolic state that occurs when the liver begins to use stored fat to produce ketones for energy. The liver is programmed to do this when the body loses access to its preferred fuel – carbohydrates – and assumes it is starving.
The ketogenic diet has been around since the 1920s, when a doctor discovered it as a way to control seizures in children with epilepsy that did not respond to other methods of treatment.
Low-carb diets like keto rely heavily on fats. At least 70% of this diet is made up of fats, but some say it’s 90%.
While you can get all of this fat from healthy unsaturated fats like avocados, tofu, nuts, seeds, and olive oil, the diet also allows for saturated fats like lard, butter, and coconut oil, as well as whole milk, cheese, and mayonnaise. Eating lots of foods high in saturated fat increases the production of LDL cholesterol, which can build up inside the arteries and restrict blood flow to the heart and brain.