Study: A Keto Diet Can Lead to Heart Scarring and Permanent Heart Damage

A new study out of China has found a deeply troubling connection between keto diets and heart damage, and it's enough to make you want to stay away from this weight loss method.

Keto diets have long been suspected of raising heart disease risk because side effects of eating 70 percent fat in your diet include raising cholesterol and potentially creating blockages in arteries. Ketosis is the most searched diet online because it works for quick weight loss by reducing your intake of carbs to 5 to 10 percent of total calories and eating 70 to 80 percent of your calories from fat and about 20 percent from protein, but keto safety has been questioned.

Keto diets put your body into a state of ketosis, or burning fat for fuel, which releases acids called ketones into the bloodstream that are now believed to be damaging to your heart muscle. The scientists looked at the cellular impact of ketones on the heart and found that when ketones are formed, they can have a detrimental impact on your heart, causing permanent scar tissue to form, which itself hinders the heart's ability to pump blood properly.

The researchers at  Fudan University in Shanghai, and Sichuan University in Chengdu, were seeking to find out of going keto might benefit the immune system. Instead, they found disturbing evidence that it could lead to atrial fibrillation or irregular heartbeat due to the scarring that occurs when the body is in ketosis. Their research "has suggested that elevated [ketone levels] is linked with poorer cardiac health, alongside various other concerning correlations between ketosis and mortality," according to an article in the online medical journal IFL Science. 

The study was done on rats, not humans, and the animals were divided into three groups and fed either a keto diet (high in fat and protein, with minimal carbs), a normal diet, or a calorie-restricted diet, for four months. At the end of that time, the rats’ hearts were analyzed to look for cellular changes and among the ketogenic dieters, the rats demonstrated higher ketones which led to the activation of a gene that inhibited normal blood flow to the heart.

That meant the heart muscle itself was left compromised. In humans, the scientists suggest, this would be the equivalent of "apoptosis" or cell death, of vital cardiac cells and fibrosis, which is essentially the scarring of healthy tissue, not something you would ever choose to be left with as a side effect of weight loss.

This is not the first study to indicate that keto diets are harmful to heart health, although there is a debate over which is worse: Being overweight, which a keto diet can help solve, or staying in ketosis for long periods of time, which has been linked to compromised heart health and specific symptoms such as irregular heartbeat, and risk factors such as higher blood lipids.

Studies such as the rat experiment have shown that in trying to solve one problem, metabolic syndrome, you may cause another, such as heart scarring. Still, there are mitigating factors. If you are at risk of heart failure from obesity, researchers have found, a keto diet may help you lose weight quickly and lower the immediate threat, but researchers now ask, at what cost?

In a tragic case of someone suffering a fatal event related to keto dieting, the world mourned the death of 27-year-old Bollywood actress Mishti Mukherjee last year when her family announced she suffered kidney failure in connection to following a strict keto diet.

The way someone chooses to follow a keto diet is as important as the concept of going into ketosis, according to doctors like Dr. Andrew Freeman, the cardiologist at National Jewish in Denver, who recently released a study that keto dieting can lead to heart disease because of the foods people eat while on the diet: People on keto diets load up on red meat, processed meat like bacon, and stay away from healthy plant-based foods like fruits, vegetables, and whole grains–which are all nutrient-rich and full of antioxidants–because they happen to contain carbs.

Dr. Freeman explained to The Beet that it's possible to eat a plant-based diet of low carbs and high fat that is healthier than the traditional keto diet which relies on a high intake of animal fat, processed meats like bacon, and eliminates fruits and vegetables to achieve ketosis. The most important thing for any long-term weight loss plan, he adds, is to eat a healthy, balanced diet, full of high fiber foods like fruits and vegetables, he explains, and not be overly concerned with fat and protein.

Keto diets are not unhealthy in theory, it's the way people do them that is, according to Dr. Andrew Freeman, the cardiologist at National Jewish in Denver, recently released a study that keto dieting can lead to heart disease because of the foods people eat while on the diet: People often load up on red meat, processed meat like bacon, and stay away from healthy plant-based foods like fruits, vegetables, and whole grains–which are all nutrient-rich and full of antioxidants–because they happen to contain carbs.

Meanwhile, another leading cardiologist, Dr. Kim Williams, former president of the American College of Cardiology, told Plant Based News that "no one should do a ketogenic diet" since the way these diets are interpreted are often full of bacon and eggs, butter, and cheese, all of which are long-term threats to a healthy heart. The saturated fat in these animal foods is known to raise cholesterol and lead to blockages and plaque that can raise blood pressure and cause heart attack and stroke. His point of view:  No one should adopt the ketogenic diet over the long term—unless weight loss is more important than lifespan.

In another unrelated study, a plant-based diet of whole foods was shown to beat out keto for weight loss and burning fat faster. The people in the study lost more weight when they ate a diet of plant-based foods (of whole foods, healthy carbs, and high-fiber, nutrient-dense fruits and vegetables) than a keto diet that was based on high animal fat and protein. So choose whether you want to keep weight off and live a long, healthy life, or lose weight quickly and risk scarring your heart forever.

The latest study is not the final word, medical researchers say, since it was done on rats and animal studies do not always translate to humans, so the study does not provide proof that a ketogenic diet will damage the human heart, but scientists often look to animal studies to give us an indication of whether drugs or foods or behaviors are safe.

So while there is still no data on the long-term effects of ketogenic diets on humans, if losing weight is the goal, an extremely low-carb diet is not as heart-healthy as one that is based on plant-based foods such as vegetables, whole grains, fruit, nuts, and seeds.

Bottom Line: A plant-based diet works better and is healthier for your heart

To lose weight and keep it off, a plant-based diet may work better than a keto diet. The keto approach has other side effects including the possibility of long-term damage to the heart.