The ketogenic (“keto”) diet has been a popular approach to weight loss in recent years. Approximately 1 in 5 Americans reports following some type of keto plan, which advocates eating very low amounts of carbohydrates and high amounts of fats.
In addition to weight loss, the keto diet may offer health benefits for several health conditions, including epilepsy, obesity and diabetes.
While this plan has helped many people, a recent study suggests that keto diets may be dangerous for your heart.
Researchers at the Centre for Heart Lung Innovation at the University of British Columbia found that regular consumption of this type of high-fat, low-carbohydrate diet was associated with high levels of LDL cholesterol (the “bad” cholesterol) and an increased risk for heart problems compared to people following more balanced diets.
A typical keto diet recommends obtaining 60 to 80% of daily calories from fat, 20 to 30% from protein and just 10% from carbohydrates, such as grains, starchy foods and high-carbohydrate fruits and vegetables.
Carbohydrates are the body’s first source of energy for everything from basic metabolism and day-to-day activities to physically demanding workouts or tasks; restricting consumption of them forces the body to break down fat instead. As fat breaks down, the liver produces chemicals called ketones for the body to use as energy (“ketogenic” refers to ketone production).
Breaking down fat may sound ideal for weight loss, but the study found it may not be so great for the heart. Even less restrictive low-carbohydrate, high-fat diets suggested an association with heart problems. The researchers analyzed data from people on “keto-like” diets consisting of no more than 25% of daily calories from carbohydrates and more than 45% from fat.
“The study found that the group following a keto-like diet had significantly higher levels of both LDL cholesterol and apolipoprotein, both of which may raise the risk of cardiovascular disease,” says James Gray, MD, a cardiologist at Scripps Clinic whose specialties include integrative cardiology.
“The study suggested a link between following a keto-like diet and having twice the average risk of major adverse coronary events, such as chest pain, heart attack, blocked arteries and stroke.”
Dr. Gray adds that the study showed only an association between the keto diet and increased cardiovascular risk, meaning that one does not necessarily cause the other.
Moreover, not everyone’s LDL cholesterol levels increased on the keto diet. Some people had the same or lower levels, suggesting that individual differences play a role — something researchers plan to study more closely.
It may be important to differentiate between the types of fats consumed. Saturated fats from animals, such as meats and dairy, may have a significantly different impact on cholesterol levels than unsaturated fats from plant-based sources, such as olive oil, nuts and seeds.
If you are following a keto diet or considering trying one, it’s important to talk with your physician about the types of foods, especially fats, that you’re eating and how they can affect your heart health.
“I recommend patients have their cholesterol levels monitored while on the diet as well as addressing other risk factors they may have, such as high blood pressure, diabetes or smoking,” says Dr. Gray.
“Also, physical activity is an important element of any weight loss or weight maintenance plan. Getting regular exercise is vital not only for weight management, but also for cardiovascular health.”