- New research shows that the keto diet could cause serious heart health problems in the long run.
- Researchers found that a “keto-like” diet was associated with higher levels of “bad” cholesterol and a doubled risk of cardiovascular events such as heart attacks and strokes.
- Experts explain the risks of a keto diet.
The ketogenic or “keto” diet has been the topic of conversation in the health world for a while. But as the diet gains in popularity, researchers are finding that the diet does pose some serious side effects. A new study found a link between a keto-like diet and heart health.
A study presented at the American College of Cardiology’s Annual Scientific Session Together With the World Congress of Cardiology suggested that a “keto-like” diet may be associated with higher blood levels of “bad” cholesterol and a doubled risk of cardiovascular events such as chest pain (angina), blocked arteries requiring stenting, heart attacks, and strokes.
Researchers utilized data from the UK Biobank and identified 305 participants who indicated that their diet during the 24-hour reporting period met the study’s definition of a low-carbohydrate, high-fat (LCHF) diet. These participants were categorized by age and sex and compared with 1,220 individuals who reported eating a standard diet.
For this study, the researchers defined an LCHF diet as consisting of no more than 25% of calories from carbohydrates and more than 45% of total daily calories from fat. They dubbed this an LCHF diet and “keto-like” because it is somewhat higher in carbohydrates and lower in fat than a strict ketogenic diet. They defined a “standard diet” as individuals not meeting these criteria and having more balanced eating habits.
Compared with participants on a standard diet, those on an LCHF diet had significantly higher levels of LDL, or “bad,” cholesterol. After adjustment for other risk factors for heart disease, such as diabetes, high blood pressure, obesity, and smoking—the researchers found that people on an LCHF diet had more than a two-times higher risk of having several major cardiovascular events, such as blockages in the arteries that needed to be opened with stenting procedures, heart attack, stroke, and peripheral arterial disease. In all, the researchers concluded that 9.8% of participants on an LCHF diet experienced a new cardiac event, compared with 4.3% of those on a standard diet—double the risk for those on the LCHF diet.
What is the keto diet and what risks does it pose to our heart health?
Ketogenic diets, or “keto,” are diets that are high in fat and low in carbohydrates, so low in carbohydrates, in fact, that it causes your body’s metabolism to break down fat and turn it into energy, explains Yu-Ming Ni, M.D., cardiologist, of Non-Invasive Cardiology at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center. Keto diets have been studied as a means for weight loss for their fat-burning capacity, he adds. “A lot of controversy has been that multiple studies have shown that high-fat, low-carb diets have generally worse outcomes from a cardiovascular standpoint than high-carb, low-fat diets that are plant-based. This study adds to that data.”
So, how exactly does going on keto affect your heart health? Turns out, there’s more inflammation with keto diets in general—high fat is generally more inflammatory, and inflammation is a key factor that regulates cardiovascular health and disease, explains Dr.Ni. “Diets high in red meat or processed meat—we definitely have evidence of the pro-inflammatory nature of those foods.”
Keto diets generally increase your cholesterol, too. This is largely because the foods that you are eating are high in cholesterol already, but high-fat, low-carb diets also affect your cholesterol levels, especially if you’re following the diet for a long time, says Dr. Ni. He reminds us that “high cholesterol is the number one factor that leads to the development of attacks and strokes.”
In general, heart attacks and strokes are related to three things: cholesterol, inflammation, and TMAO, explains Kim Williams, M.D., past president of the ACC and an expert on cardiovascular disease prevention and nutrition. “It’s important to keep those three things from accumulating in your bloodstream because they promote plaque,” he adds. But when it comes to the keto diet, it raises all three of those factors. “When you drop weight, your blood pressure goes down, so you would think that your heart disease risk would go down too—but it doesn’t.”
The bottom line
The keto diet may work for some in terms of short-term weight loss, but these new findings demonstrate the dangers of long-time commitment. It could pose serious risks for your heart health by raising cholesterol levels and promoting inflammation.
For your long-term health, keto is not the way to go, says Dr. Ni. He explains that it’s too much stress on the body, too much fat, too high of cholesterol. “Long-term ketogenic diets are not as healthy as plant-based higher carb diets such as the mediterranean diet or the DASH diet. I would advocate for those diets for daily maintenance.” However, the key caveat is that the keto diet can be effective for short-term (3 to 6 months) weight loss, if that’s what you’re aiming for, adds Dr. Ni.
In fact, there are different kinds of keto diets, and not all pose the same threat to your heart health. For example, Dr. Williams explains how a vegan, or plant-based, keto diet may actually lower your risk for heart attacks and stroke. “Vegan keto, where you do peanut butter, whole grains, and avoid carbs, use olive oil for fat, actually lowers mortality. So it’s not keto itself, it’s keto with animal products.”
If you’re considering the keto diet, be sure to discuss it with your doctor first, because you could be doing more harm than good to your heart.
Madeleine, Prevention’s assistant editor, has a history with health writing from her experience as an editorial assistant at WebMD, and from her personal research at university. She graduated from the University of Michigan with a degree in biopsychology, cognition, and neuroscience—and she helps strategize for success across Prevention’s social media platforms.