Fact-checked by Dr. Anthony Gustin, DC, MS.
Written by Emily Ziedman
Heart disease is the leading cause of death in the world (that’s right — the entire world)[*].
It’s the biggest public health issue in America, with heart disease numbers growing every year.
Researchers cite all kinds of different culprits in heart disease: cholesterol levels, blood sugar, inflammation, obesity, and — perhaps above all else — eating too much fat.
Dietary fat has been villainized for years as the number one cause of heart disease, and many people still shy away from a high-fat keto diet for fear that eating saturated fat will lead them straight to a heart attack.
But more and more research shows that a high-fat, low-carb diet like the ketogenic diet won’t increase your risk of heart disease.
In fact, eating a keto diet can reverse a lot of risk factors for heart disease, including high blood pressure, type 2 diabetes, insulin resistance, triglyceride levels, excess body fat, and more.
What is Heart Disease?
Heart disease is the leading cause of death for both men and women in the U.S., with coronary heart disease (CHD) causing about 50% of deaths[*].
CHD is caused by a buildup of plaque in the walls of your arteries, which supply blood, oxygen and nutrients to your heart and other parts of your body.
Think of plaque as a waxy substance that builds up in layers like the plaque on your teeth. The plaques that can form in your arteries are made up of cholesterol, fat, calcium, and other substances.
In a process known as atherosclerosis, the plaques keep growing bigger, and can eventually begin to narrow and block blood flow your heart and around your body.
Eventually, your heart muscle will begin to weaken which can lead to heart failure, a condition where the heart can no longer pump normally.
When the blood flow to your heart becomes blocked enough, you have a heart attack[*].
Does The Keto Diet Cause Heart Disease?
The idea that the keto diet can cause heart disease is tied to the thought that dietary fat is bad for your heart. Here’s how that idea came about.
Back in the 1970s, correlational research linked saturated fat consumption to heart disease. That means that in huge worldwide datasets, it looked like people who ate more saturated fat had more heart attacks.
They did not take into account other lifestyle factors like exercise and smoking.
Scientists put forth a theory: eating saturated fat increases your LDL (“bad”) cholesterol, which clogs your arteries and eventually leads to arterial plaques.
The American Heart Association (AHA) jumped on board and put out warnings against consuming saturated fats from sources like meat, butter, and coconut oil.
And thus began the low-fat diet craze. It was good-bye butter and meat, and hello fat-free dairy and low-fat pre-made meals.
But as the American diet went from high-fat to low-fat, an interesting trend happened: Even when Americans drastically decreased their fat consumption, obesity skyrocketed. In fact, from 1988 to 2008 the number of people in the United States that are obese doubled[*].
The connection between obesity and heart disease is clear and very strong. Risk factors for heart disease such as blood pressure, blood lipids, and inflammation all increase as obesity increases[*].
So in effect, as Americans stopped eating fat to protect their hearts, they unknowingly increased their risk for heart disease.
But there must have been some compelling research to make the AHA put out such strong warning, right?
Not so much. More recent research shows that there isn’t actually much of a link between saturated fat and heart disease, or fat intake in general and heart disease.
In 2010, a group of researchers did a meta-analysis on saturated fat and heart disease.
They took all the existing studies to-date and looked at them as a whole. They concluded that there’s no benefit in switching out saturated fat with unsaturated fat.
In fact, eating more unsaturated fat increased the risk for heart disease if the polyunsaturated fats were mostly omega-6 (from vegetable oils, margarine, and so on), without enough omega-3s to balance them out[*].
As science progresses, it’s becoming clearer and clearer that there’s no meaningful link between saturated fat consumption and risk of heart attack.
What’s The Deal With Cholesterol and Heart Disease?
When you hear that someone has high cholesterol, your mind most likely goes right to heart disease. Cholesterol and heart disease have been linked together so intimately that sometimes one feels like a synonym for the other.
Replacing saturated fat from meat and butter with unsaturated fat from vegetable oil does lower your cholesterol.
However, much like what happened with saturated fat, the cholesterol-heart disease connection has been poorly understood and even more poorly explained.
Both the size of the LDL particle and the number of particles seem to play a more significant role in the development of heart disease — as opposed to the mere presence of LDL cholesterol in your blood[*][*].
In other words, there’s good LDL and bad LDL.
Smaller, more dense LDL particles have a stronger correlation to heart disease than the big fluffy LDL particles. This is because the smaller LDL particles can more easily get into your artery walls and contribute to the plaques that eventually lead to heart disease[*].
So how do you make sure your LDL particles are nice and fluffy? Research has shown that the ketogenic diet decreases atherogenic dense LDL and increases the larger, fluffier LDL particles that are less likely to contribute to plaques on your artery walls[*].
3 Reasons The Keto Diet is Heart-Healthy
Some of the biggest risk factors for heart disease are:
- Insulin resistance (and, if insulin resistance goes unchecked, type II diabetes)
Let’s take a look at these heart disease risk factors and see how the keto diet affects each of them.
#1: A Ketogenic Diet Reverses Insulin Resistance and Type II Diabetes
There’s a strong correlation between insulin resistance and type II diabetes and the risk of heart disease. In fact, the AHA considers diabetes to be one of the seven major risk factors for developing heart disease[*].
Here’s the connection — When you have insulin resistance (or diabetes), you have too much glucose (sugar) roaming around your bloodstream.
Over time, that excess glucose can damage your blood vessels along with the nerves that control your blood vessels. This can ultimately lead to heart disease[*].
People who are 65 or older with diabetes have a 68% chance of dying from heart disease[*].
Eating a keto diet is one of the best things you can do for insulin resistance or diabetes.
By avoiding carbohydrates that turn into excess sugar in your blood, you’re protecting your blood vessels from the potential damage that blood glucose can cause, which in turn protects you from heart disease.
A keto diet is so good at reducing blood sugar levels that many people are able to come off of their diabetes medications entirely[*]. That makes a major difference when it comes to heart disease risk.
#2: A Ketogenic Diet May Reduce Inflammation
New studies suggest that inflammation may damage your arterial wall and cause cholesterol to oxidize in your arteries, forming plaques that drive heart disease[*].
In one study, rats were fed a ketogenic diet for 14 days. At the end of the 14 days, they showed a significant drop in chronic inflammation, as well as decreased peripheral and brain inflammation[*].
Ketones themselves may have anti-inflammatory properties. Specifically, beta-hydroxybutyrate — one of the main sources of fuel you use on ketosis — causes a dramatic decrease in inflammatory response[*].
#3: A Ketogenic Diet is Great for Weight Loss and Fights Obesity
Obesity is one of the major contributors to heart disease.
The correlation comes not just from the increased body fat itself, but from factors that come along with obesity like increased blood pressure, risk of stroke, and diabetes.
Obesity is also linked to a large left heart ventricle, which is a common cause of heart failure[*].
If you’re looking to lose some weight, the ketogenic diet is an excellent option. You’ll not only shed extra pounds, but your hunger will also diminish so you won’t be walking around craving sugar[*].
A study of more than 19,000 obese patients found that a keto diet was the best way to cause rapid weight loss.
Even better, when researchers followed up with the participants a year later, close to 85% of those who lost weight had kept the weight off.
That’s very rare — most people gain weight back — and it speaks to how sustainable a ketogenic diet is. Researchers reported no adverse effects and determined that the keto diet was a safe, effective, and inexpensive treatment for obesity[*].
Is Keto Healthy If You Already Have Heart Disease?
The keto diet is looking pretty good for preventing heart disease, but what if you already have heart disease or are at risk?
Eating a keto diet can reverse or decrease a lot of risk factors for heart disease, including inflammation, high blood lipids, obesity, high blood pressure, and insulin resistance/diabetes — all factors you want to control if you have heart disease[*],[*],[*],[*].
That said, not all keto diets are created equal. If you’re going to try keto, make sure you choose a high-quality keto diet that’s rich in healthy fats and full of low-carb vegetables that provide an abundance of nutrients, including fiber, omega-3s, and an array of micronutrients.
Stay away from processed omega-6 oils and trans fats.
While there’s no evidence that a ketogenic diet is harmful to your heart, eating a poor quality diet full of processed foods and trans fats can definitely impact your heart health — whether it’s low-carb or not[*].
So keeping your keto diet clean and healthy is just as important as keeping your carbs low.
The Takeaway: Does Keto Cause Heart Disease?
Plain and simple, the keto diet does not cause heart disease.
In fact, following a low-carb, high-fat diet may be one of the best ways to prevent heart disease.
The anti-inflammatory, blood sugar regulating, bad cholesterol lowering, and anti-obesity effects of the ketogenic diet all make it a great option for decreasing your risk of heart disease.
Ready to try the ketogenic diet? Try the Keto Kickstart — a simple 30-day challenge to get you into ketosis, quickly and painlessly.