Keto for Heart Health: A Science-Based Guide

One of the main concerns about the Keto diet is that high-fat diets are bad for your heart. People worry that all that fat will clog your arteries and accelerate heart disease.

But that’s not how heart disease works. Fat doesn’t—and can’t—“clog” your arteries. While the type of fat you eat can affect your heart disease risk, many people are confused about which fats are actually heart-healthy.

So, is Keto good for heart health? What does the science say? And what are the risks?

We’ll get to those questions soon, but first, let’s cover some basics.

What Is Keto?

The Keto diet is a low-carb eating plan that involves getting 55 to 75 percent of your calories from fat, 15 to 35 percent from protein, and less than 10 percent from carbohydrates. Maintaining these macro ratios—especially keeping carbs low—helps your body enter a fat-burning state called ketosis.

Keto is best known as a weight-loss diet. Not only do people burn more fat on Keto, but they also tend to eat fewer calories, which is a great combination for losing weight.

But Keto has many other potential benefits beyond weight loss, including:

• More stable energy
• Clearer thinking
• Reduced cravings and hunger
• Lower inflammation
• Lower blood sugar and insulin (Keto shows promise in reversing type 2 diabetes)
• Potential anti-cancer effects

We’ll talk later about how these benefits might help your heart. First, let’s talk about heart disease.

What Is Heart Disease?

Heart disease, also known as cardiovascular disease (CVD), refers to a range of problems with the circulatory system. These problems include insufficient blood supply to parts of the body, inadequate blood supply to the brain (stroke), heart attacks, and plaque buildup in the arteries.

The last problem—called atherosclerosis—accounts for up to half of all CVD cases. Atherosclerosis is known as the “silent killer” because plaque builds up without symptoms for years, then suddenly breaks off to cause a heart attack, stroke, or sudden death.

That’s why we look at blood biomarkers like LDL particles, inflammation (e.g., CRP, troponin), blood pressure, and blood sugar to assess heart disease risk. These factors work together—not alone—to drive the formation of atherosclerotic plaques.

Yes, LDL particles (which carry cholesterol to tissues) are linked to atherosclerosis. But if inflammation and blood pressure are low, the particles are less likely to stick to the artery walls, oxidize, and attract the plaque-forming immune system. High triglycerides and low HDL (the “good” cholesterol) are also closely linked to heart disease risk.

We need to look at the full picture of risk factors. Let’s see how Keto might influence them.

Can Keto Improve Heart Health?

Unfortunately, there are no long-term studies on Keto for primary cardiovascular outcomes like heart attacks, strokes, or mortality. Conducting such studies would require deep pockets and years of patient follow-up.

So, what’s the next best thing? We can look at how Keto affects secondary outcomes like obesity, high blood pressure, high blood sugar, high LDL, low HDL, high triglycerides, and inflammation. And the data there is promising.

In a 2004 study, a 24-week ketogenic diet led to significant weight loss, lower blood sugar, lower triglycerides, and lower LDL in 83 obese individuals. All of these changes represent improvements in cardiovascular disease risk.

There’s also data on Keto for type 2 diabetes, which is closely linked to heart disease. In the year-long Virta Health study, Keto improved most heart disease risk factors in nearly 300 people with diabetes.

One of these factors was CRP (C-reactive protein), a marker of chronic inflammation linked to increased heart disease risk. Keto may help lower inflammation by:

• Reducing excess body fat
• Preventing high blood sugar
• Suppressing the NLRP3 inflammasome

For overweight and obese individuals, any weight loss on Keto is a positive move for heart health. Now, let’s look at the other side of the coin.

Risks of Keto for Heart Health

Dietary fat doesn’t clog your arteries, but certain types of fat are more heart-healthy than others. Therefore, the heart benefits (or risks) of a Keto diet partly depend on which fats you’re eating.

Most people know that trans fats (e.g., margarine) are bad for your heart and that monounsaturated fats (e.g., avocados, olive oil) are heart-healthy. The science supports both of these common beliefs.

The confusion mostly lies around saturated and polyunsaturated fats. Let’s clear that up, shall we?

Saturated fat has been demonized for decades as bad for your heart, but this conventional wisdom deserves a closer look. For example, two massive meta-analyses of over one million people found no link between saturated fat consumption and cardiovascular disease risk. However, saturated fat is well-documented to increase LDL, which might explain why some people see a spike in this heart disease risk factor on Keto.

Polyunsaturated fat (PUFA), on the other hand, is celebrated as good for your heart. And for omega-3 polyunsaturated fats, this is generally true.

But when it comes to vegetable oil PUFAs, we shouldn’t be so celebratory. Consider that:

• Excess consumption of soybean oil (and other vegetable oils) has been shown to fatten mice and is linked to the American obesity epidemic.
• Consuming heated vegetable oils creates dangerous particles called oxidized lipids that likely accelerate heart disease progression.

So, what does a heart-healthy Keto diet look like?

Best Low-Carb Foods for Heart Health

A whole-foods Keto diet is probably heart-healthy for most people. If you avoid sugar, vegetable oils, and packaged foods, you’re already ahead of the game.

But if your LDL spikes on Keto, you might consider a Mediterranean Keto diet. On Mediterranean Keto, you eat fish, non-starchy vegetables, olive oil, and avocados, but limit other Keto staples like meat, butter, and other sources of saturated fat.

A few uncontrolled studies suggest that Mediterranean Keto improves heart disease risk factors, but more data is needed. Still, there’s minimal risk in following a low-carb Mediterranean template.

If your cholesterol is still high on Mediterranean Keto, consider adding back some complex carbohydrates, like quinoa and sweet potatoes.

Thinking Long-Term

The Keto diet has been shown (mostly in obese individuals and those with diabetes) to improve heart disease risk factors like high blood pressure, high blood glucose, high LDL, and inflammation. But in leaner populations, Keto may increase LDL.

How will Keto affect your heart health? Answering that question might take some detective work.

To stay on top of your cardiovascular disease risk, periodically check your biomarkers (preferably under the guidance of a medical professional). For example, if LDL is too high, try limiting saturated fat and retesting in a month or two.

And remember, heart health is a lifelong journey. Do your future self a favor by making positive changes sooner rather than later.