How Does Keto Affect Cholesterol?

Many people worry about high cholesterol on a Keto diet. Should you be worried too?

That depends. For some people, Keto improves this heart disease risk factor. For others, however, it does not. 

It’s a tricky topic. Cholesterol levels don’t just depend on diet, but also on genes and body composition. And there are lots of ways to measure what we call “cholesterol.” 

Also, we should keep in mind that cholesterol isn’t the only heart disease risk factor. It’s just one of many. 

Today you’ll learn why cholesterol matters, how to measure cholesterol, and the scoop on Keto and cholesterol. Let’s dive in. 

What Is Cholesterol?

Cholesterol is a sterol (a type of organic molecule) that structures cell membranes and helps synthesize hormones. It’s crucial for animal life. 

When people talk about their “cholesterol,” they’re generally talking about the cholesterol within lipoproteins—tiny transport vessels in your bloodstream that shuttle cholesterol to and from your cells. 

There are several types of lipoproteins, but the two most common (and relevant to cholesterol testing) are low-density lipoprotein (LDL) and high-density lipoprotein (HDL).[*]

LDL is known as “bad cholesterol” because higher levels of LDL cholesterol are correlated with higher heart disease risk.[*] But to say LDL is “bad” is overly simplistic. LDL particles serve the essential function of delivering cholesterol, triglycerides, and other nutrients to cells. We couldn’t live without them. 

HDL is known as “good cholesterol” because higher levels are correlated with lower heart disease risk.[*] Why? The theory is that higher cholesterol concentrations within HDL particles suggest more cholesterol is being “cleaned up” from the arteries. Unfortunately, attempts to reduce heart disease risk by pharmacologically raising HDL levels have failed.[*] 

It’s time to stop calling HDL and LDL “good” and “bad” cholesterol. Neither label holds up to scientific scrutiny.   

How To Measure Cholesterol Levels

A standard lipid panel measures the concentration of cholesterol within each lipoprotein. This panel includes[*]:

• TC (total cholesterol): over 200 is considered high
• LDL-C (LDL-cholesterol): over 160 is considered high
• HDL-C (HDL-cholesterol): under 40 is considered low
• Triglycerides: over 150 is considered high

But the standard lipid panel isn’t the only relevant cholesterol test. It’s probably not even the best. 

For instance, evidence suggests that tests like APoB and LDL-P that measure the number of LDL particles in the bloodstream (as opposed to cholesterol within each LDL particle) track more closely with heart disease outcomes.[*] 

It also appears that smaller LDL particles are more dangerous than larger LDL particles, all things equal, from a heart disease risk perspective.[*] 

So whether or not your standard lipids look normal, you may want to follow up with more advanced testing. 

What Affects Cholesterol?

Diet is a significant influencer of cholesterol levels. Consider the following:

• High saturated fat intakes are correlated with higher LDL-C, HDL-C, and TC, but not increased heart disease risk.[*][*][*]  
• A Ketogenic diet can either raise or lower cholesterol (more on that soon)[*][*]
• A high-sugar diet (the standard diet in America) is correlated with higher cholesterol levels, obesity, and other heart disease risk factors.[*] 

On the last bullet, it’s hard to untangle diet, obesity, and one’s cholesterol profile. Cholesterol is elevated in both obese and diabetic populations[*][*], and diet is a major driver of these conditions. 

Genes also affect cholesterol levels. For example, those with a genetic condition called familial hypercholesterolemia (FH) tend to have total cholesterol levels north of 300 and often suffer heart attacks or strokes decades earlier than the general population.[*] They are living examples of the risks of high cholesterol.

A variety of other health conditions can raise or lower cholesterol levels. Hypothyroidism (low thyroid), for instance, can decrease LDL breakdown and the rate your liver clears LDL particles, causing them to accumulate.[*]

We’ll talk more about LDL clearance later. Let’s turn to Keto now. 

How Might Keto Affect Cholesterol?

Depending on the person, a low-carb Keto diet may improve or worsen cholesterol numbers. 

In obese people and those with diabetes, Keto generally improves heart disease risk factors like LDL, HDL, TC, triglycerides, blood pressure, obesity, and inflammation. Here are a few examples:

• 66 obese people with high or normal cholesterol had lower LDL and higher HDL after 56 weeks of Keto dieting[*]
• Another study found similar cholesterol improvements in 83 obese people who ate Keto for 24 weeks[*] 
• A recent meta-analysis (review of studies) found that Keto raised HDL and lowered triglycerides in overweight or obese people with or without type 2 diabetes[*]

For some people, however, LDL rises on a Keto diet. These people tend to be lean and non-diabetic. 

For instance, one study found that three weeks of Keto dieting raised LDL-C by 39% in young, healthy women.[*] The authors surmised that an increase in dietary saturated fat was to blame. 

How To Maintain Healthy Cholesterol On Keto

We still don’t know the best diet for high cholesterol, but the data suggests that Keto can improve cholesterol profiles in obese people and those with diabetes. It’s a promising drug-free therapy for these populations. 

But what if your LDL spikes on Keto? Some people say not to worry about it. That other risk markers (like triglycerides or CRP) are more important. That high cholesterol alone doesn’t cause heart disease. 

Maybe they’re right. We don’t have good long-term data on otherwise healthy people that develop high LDL on Keto. 

But since high LDL is a well-established heart disease risk factor in other populations, it’s probably wise to play it safe.[*] Beyond consulting with your doctor to manage your cholesterol, be mindful of these 3 dietary considerations:

#1: Replace saturated with monounsaturated fat

Keto is a high-fat diet. Because of this, going Keto entails eating more butter, animal fat, coconut oil, and other sources of saturated fat than most people otherwise would. 

And as we covered earlier, higher intakes of saturated fat are well understood to raise cholesterol levels.[*] That’s why Keto and high cholesterol often go hand in hand. 

One way to mitigate high cholesterol on Keto? Replace saturated fats with monounsaturated fats. 

The best sources of monounsaturated fats are olives, avocados, and nuts (macadamia nuts are particularly high). Instead of a fatty ribeye, you have a chicken and spinach salad drenched with olive oil. Instead of cooking with butter, you cook with avocado oil. You get the idea. 

#2: Increase fiber intake

Fiber binds to cholesterol in the gut, carries it out through stool, and reduces your circulating pool of cholesterol.[*] Because of this, eating fiber-rich low-carb veggies like kale, spinach, and broccoli is a great way to maintain healthy cholesterol levels without kicking yourself out of ketosis. 

#3: Have more carbs

When you restrict carbs, it keeps blood sugar and insulin levels low. This sends the signal for your body to burn fat and make ketones. 

But low insulin has other effects. One of them, unfortunately, is to slow your liver’s clearance of LDL particles.[*] This can lead to higher LDL levels. 

By stimulating insulin release, eating carbs can help you clear LDL faster. You can pulse carbs periodically (the Cyclical Ketogenic diet) or simply increase daily carbs until your cholesterol improves. 

The important thing is to work alongside a registered healthcare professional to monitor your cholesterol levels as you tinker with your routine. Since everyone is different, that’s how you’ll know what’s working.