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Is the Keto Diet Bad for Your Heart?

Medically reviewed by Lisa Booth, RDN
Written by Emily Brown
Posted on July 25, 2025

Key Takeaways

  • While the keto diet is often discussed for weight loss, its high-fat approach raises concerns about potential effects on heart health for people living with obesity.
  • The ketogenic diet requires getting 70 to 80 percent of daily calories from fat, which is much higher than standard dietary guidelines and may increase cholesterol levels in some people.
  • Before starting a keto diet, talk with your healthcare provider or cardiologist who can help assess whether it's appropriate given your individual health history and heart health concerns.
  • View full summary

You’ve surely heard people rave about the keto diet as a way to lose weight, but is it bad for your heart? Obesity increases the risk of other health conditions like high blood pressure and heart disease. Living with obesity can mean being mindful of foods to eat and those to avoid to promote cardiac health.

It can be hard to know which diets to follow, if any. The keto diet may have short-term health benefits for some people, but key parts of the diet go directly against guidelines for a heart-healthy diet.

Learn more about the keto diet and heart health, including risk factors to consider for people diagnosed with obesity.

What Is the Keto Diet?

The ketogenic diet (keto diet) is a low-carbohydrate, high-fat diet that has been used for a long time to help manage diseases like epilepsy and diabetes. The keto diet is different from other low-carb diets because it focuses on eating a lot more fat.

In a keto diet, 70 percent to 80 percent of your daily calories should come from fat. For reference, the Dietary Guidelines for Americans 2020-2025 recommend that 20 percent to 35 percent of your daily calories should come from fat.

The idea of the keto diet is to use fat instead of carbohydrates for energy. Carbohydrates break down into glucose, which is the main source of energy for all cells in the body. When the body doesn’t have enough glucose, it breaks down stored fat into ketones for energy. When your body is using ketones for energy, it’s called ketosis. The keto diet is named for these ketones, which have possible benefits such as promoting weight loss, yet the research is still limited.

The Keto Diet and Heart Disease

Short-term studies have shown that the keto diet can improve some risk factors for cardiovascular disease (heart disease), such as:

  • High-density lipoprotein (HDL) cholesterol (the “good” cholesterol)
  • Body weight
  • Blood glucose levels
  • Triglycerides (fat in blood)

However, other studies have found conflicting results. For instance, a review of available studies from the journal Circulation found that most of the improvements noted above were not maintained after one year.

More research is needed to better understand whether the keto diet is helpful in the long term, especially for people who have heart disease or are at risk of heart disease. Below, we discuss some factors to know about the keto diet and heart health.

Weight Loss

The keto diet has been shown to help with short-term weight loss. There are several ways the keto diet is thought to promote weight loss, such as by reducing food cravings after eating foods with high-fat content.

Losing weight with obesity can help prevent and improve health problems like high blood pressure and high cholesterol. However, research on weight loss from the keto diet is limited to the short term, meaning it’s unknown how weight may change over the long term. In addition, weight loss on the keto diet may create new problems. For example, even if you lose weight on the keto diet, your cholesterol levels may still go up.

Unhealthy Amounts of Saturated and Trans Fat

Because the keto diet is rich in fat, following the diet usually means that you end up eating more saturated fat. In fact, the keto diet encourages high amounts of saturated fat, such as from butter and palm and coconut oils. And it doesn’t discourage protein sources high in saturated fat, such as pork, bacon, and beef, which cardiologists recommend limiting for those at risk for heart disease. For example, the American Heart Association (AHA) recommends choosing lean meats to reduce the amount of saturated fat you consume.

Eating a lot of saturated fat and trans fat (found in fried foods, meats, dairy, and baked goods) may increase your cholesterol and risk for heart disease. Some doctors say the saturated fat intake from the keto diet can reach unhealthy levels, even if you choose all healthy fats, like those found in fish.

Increased Cholesterol

The keto diet has been shown to increase total blood cholesterol levels, including low-density lipoprotein (LDL) cholesterol. LDL cholesterol is known as the “bad” cholesterol, as it can increase your risk for heart disease. A study published in the Journal of the American College of Cardiology found that people on a low-carbohydrate, high-fat (LCHF) diet had significantly higher total cholesterol levels compared to those following a standard diet. Furthermore, severely high cholesterol was almost twice as common in people following the LCHF diet.

This rise in cholesterol can be especially unhealthy for people living with heart disease. When there’s too much cholesterol in the blood, the arteries can become narrowed and less flexible, and are more prone to blood clots. This condition increases the risk of having a stroke or heart attack. The study showed that people on the LCHF diet were more than twice as likely to experience serious heart issues, such as heart attacks, strokes, or sudden chest pain, compared to those on a regular diet.

Of note, the LCHF diet in the study was defined as more than 45 percent of daily calories from fat and less than 25 percent of daily calories from carbohydrates. The typical keto diet recommends 70 percent to 80 percent of calories from fat and only 5 percent to 10 percent from carbohydrates. The LCHF diet in the study was considered “keto-like,” and a strict keto diet may have different results. However, it’s important to consider whether the foods the participants consumed were processed versus whole foods, which are better for cholesterol and heart health.

Limited Intake of Whole Grains and Fruits

Although most diets are limiting by nature, the keto diet is especially limiting due to its strict rules on carbohydrate intake. This situation can be problematic, as many healthy foods contain carbohydrates. For example, the keto diet restricts the intake of heart-healthy foods like whole grains and whole fruits because of their carbohydrate content.

The American Heart Association released a statement saying that the keto diet challenges AHA dietary guidelines because it limits these healthy foods and promotes eating more animal-based foods. The AHA adds that restricting whole grains, legumes, and whole fruit may lead to nutrient deficiencies and missed opportunities for getting beneficial phytochemicals (protective plant-based compounds) from these foods.

Experts Don’t Know the Long-Term Impact of Ongoing Ketosis

Experts note the need for more research on how the keto diet affects health over time. It’s unclear what being in a long-standing state of ketosis from the keto diet can do to the body in the long run.

Some MyObesityTeam members are wary of the effects of the keto diet. “Keto scares me, but I have done South Beach and had OK results years ago,” one member shared. It’s best to seek professional advice if you have questions or concerns about the keto diet.

Talk to Your Doctor About the Keto Diet

Not only is the keto diet unbalanced, but it can be hard to follow because it’s very restrictive. “The carbs are what I struggle most with. I love bread, pasta, and rice. That is what I crave now,” commented a member of MyObesityTeam.

If you’re thinking about the keto diet, it’s best to talk to your doctor or cardiologist before starting. They can help you assess whether a keto-like diet is a good idea given your health history and heart health. Your doctor may refer you to a registered dietitian or nutritionist for expert advice on maintaining a heart-healthy diet.

The key is to find an eating plan that is both heart-healthy and realistic for you to maintain. Each person is different, and what works for one may not work for another. Consulting with a dietitian can help you tailor a diet plan that’s right for you and easy to stick with.

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