Keto for Heart Health: A Science-Based Guide

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

But that’s not how heart disease happens. Fat doesn’t (and couldn’t) “clog” your arteries. And though the type of fat you eat can influence heart disease risk, most people are confused about which fats are heart-healthy. 

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

We’ll answer these questions soon, but first, let’s cover some basics.

What Is Keto?

The Keto diet is a low-carb eating plan that entails eating 55 to 75 percent of your calories from fat, 15 to 35 percent from protein, and under 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 folks burn more fat on Keto, but they tend to eat fewer calories.[*] This is a good combo for fat loss. 

Yet Keto has many potential benefits beyond weight loss, including:

• More stable energy
• Clearer cognition
• Reduced cravings and hunger pangs[*]
• Lower inflammation[*]
• Lower blood sugar and insulin (Keto shows promise for reversing type 2 diabetes)[*]
• Potential anti-cancer effects[*]

Later, we’ll cover how these benefits may help your heart. First, though, let’s talk about heart disease. 

What is Heart Disease?

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

The last problem (known as atherosclerosis) accounts for up to half of CVD cases.[*] Atherosclerosis is called the “silent killer” because the plaque accrues without symptoms for years, then one day breaks off to cause a heart attack, stroke, or sudden death. 

That’s why we look at blood biomarkers like LDL particles, inflammation (i.e. CRP, Troponin), blood pressure, and blood sugar to assess heart disease risk. They 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 in the artery wall, oxidize, and draw the attention of the plaque-forming immune system. High triglycerides and low HDL (the “good” cholesterol) are also very closely linked to cardiac risk.[*]

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

Can Keto Improve Heart Health?

Unfortunately, there aren’t any long-term studies on Keto for primary CVD outcomes like heart attack, stroke, or mortality. Running these studies would take deep pockets and years of patient observation. 

The next best thing? Monitor 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 people.[*] All of these changes represent improvements in CVD risk. 

There's also data on Keto for type 2 diabetes, a condition closely linked to heart disease. In the year-long Virta Health study, Keto improved most heart disease risk factors in nearly 300 folks 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[*]

Also, for overweight and obese folks, any weight loss on Keto represents a positive move for heart health. Let’s look at the other side of the coin now.

Risks of Going Keto for Heart Health

Dietary fat doesn’t clog your arteries, but certain types of fat are more heart-healthy than others. And so, the heart benefits (or risks) of a Keto diet depend partly on which kind of fat is on the menu. 

Most people know that trans fats (i.e., margarine) are bad for your heart and that monounsaturated fats (avocados, olive oil, etc.) are heart-healthy. The science supports both of these popular beliefs.[*][*] 

The confusion is mostly around saturated and polyunsaturated fat. Let’s clear it up, shall we?

Saturated fat has been maligned for decades as bad for your heart, but this piece of conventional wisdom warrants a closer look. For instance, two massive meta-analyses of over one million people found no link between sat fat consumption and CVD risk.[*][*] Nonetheless, saturated fat is well-documented to increase LDL[*], perhaps explaining why some folks may see a spike in this CVD risk factor on Keto.[*] 

Polyunsaturated fat (PUFA), however, is celebrated as good for your heart. And for omega-3 polyunsaturated fats, this is generally true.[*] 

But when it comes to vegetable oil PUFA, we shouldn’t be celebrating. Consider that:

• Excess consumption of soybean oil (among other veggie oils) fattens up mice and has been 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 doing better than most. 

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 to eating a low-carb Mediterranean template. 

If your cholesterol still looks 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 people and people 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 may take some sleuthing. 

To stay on top of your CVD risk, periodically check your biomarkers. (Preferably under the guidance of a medical professional.) For instance, if LDL looks too high, try limiting saturated fat and retesting in a month or two. 

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