If you’ve recently switched to a low-carb, high-fat, or carnivore-style diet and noticed a spike in your cholesterol numbers, you’re not alone. It’s a common trend—and one that can cause alarm if you or your doctor are only looking at the surface of your lipid panel. But there’s more to the story, and the numbers might not mean what you think.

In this blog, we’ll explore why cholesterol may increase on a low-carb diet, what these changes actually reflect in the body, and why higher cholesterol doesn’t always equal higher risk.

First: What Is Cholesterol, and Why Do We Need It?

Cholesterol is a waxy, fat-like substance that’s vital for health. It’s used to:

• Make hormones like estrogen, progesterone, testosterone, and cortisol
• Build healthy cell membranes
• Create bile acids for digestion
• Support vitamin D production
• Optimize brain function

Your Body Makes Most of Your Cholesterol

It might surprise you to learn that only about 20% of your blood cholesterol comes from the food you eat. The other 80% is produced by your liver, which tightly regulates cholesterol levels based on your body’s needs. This means that eating foods high in cholesterol—like eggs or red meat—doesn’t necessarily raise your cholesterol levels the way we once thought. In fact, for many people, dietary cholesterol has little impact on blood cholesterol numbers.

Instead, cholesterol levels are influenced by insulin resistance, inflammation, stress, hormones, genetics, and overall metabolic health. That’s why improving gut health, blood sugar balance, and reducing inflammation often has a bigger effect on your lab work than simply cutting out cholesterol-rich foods.

Why Cholesterol Often Increases on Low-Carb or Carnivore Diets

When someone moves to a very low-carb or zero-carb diet (like carnivore), they’re typically increasing healthy fats and proteins while reducing sugars, grains, and processed carbs. This shift:

• Promotes fat burning over sugar burning (known as ketosis)
• Improves blood sugar regulation and insulin sensitivity
• Reduces inflammation in many individuals

However, this dietary shift can also lead to increases in total cholesterol and LDL (“bad”) cholesterol—especially in leaner individuals or those with very low insulin levels.

Some potential reasons:

• Fat transport increases: Your body uses LDL particles to carry fat (including cholesterol) to cells that need energy or repair.
• Weight loss mobilizes fat stores: As stored fat is released, cholesterol also enters the bloodstream.
• Improved liver function can mean more efficient cholesterol production and transport.

This isn’t necessarily a bad thing. In fact, several recent studies show these changes often reflect improved metabolic health—not worsening heart disease risk.

The Importance of LDL Particle Size and Number

When evaluating cholesterol, particle size matters more than total cholesterol levels.

🔹 Small, dense LDL particles are more likely to oxidize and penetrate arterial walls, contributing to plaque buildup and inflammation.

🔹 Large, buoyant LDL particles are less harmful and not strongly associated with cardiovascular disease (CVD).

Low-carb high-fat diets result in a decrease in small LDL particle number indicating a decrease in cardiovascular disease risk.

As shown in the literature review above, a meta-analysis of 38 randomized trials by Falkenhain et al (2021) found that low-carb diets decreased the numbers of total LDL and small LDL particles and increased LDL particle size.

Similarly, a review by Froyen (2021) found that higher fat diets decreased the number of small, dense LDL particles and/or increased the number of large and buoyant LDL particles compared to lower fat diets.

Both of these changes indicate a reduced risk of cardiovascular diseases.

Research has shown that small, dense and oxidized LDL particles are those that contribute to the plaque formation in the inner lining of the arteries and may directly associate with the risk of cardiovascular diseases.

Therefore, a decrease in the number of small LDL particles on a low-carb diet potentially means a lower risk of heart diseases.

Large LDL particles, however, have been found to be not associated with an increased risk of heart diseases.

In a study involving 2072 men who were followed for a period of 13 years, it was found that large LDL sub-fractions were not associated with an increased risk of CVD events but small LDL sub-fractions were.

Accordingly, an increase in LDL particle sizes (which is likely to be the primary cause of the increase in LDL cholesterol on low-carb high-fat diets) indicates a reduced risk of heart diseases.

What to Look at Instead of Just LDL-C

When assessing heart disease risk, ask for more advanced labs beyond the standard lipid panel. Useful tests include:

• LDL-P (particle number)
• ApoB (Apolipoprotein B)
• Triglyceride:HDL ratio (ideal is under 2:1)
• hsCRP (marker of inflammation)
• Lp(a) (a genetically influenced risk factor)

These give a more complete picture of your metabolic and cardiovascular health than just total or LDL cholesterol.

Bottom Line

A rise in cholesterol on a low-carb diet doesn’t automatically mean your heart disease risk is increasing. Often, it reflects a shift toward larger, less harmful LDL particles and improved metabolic health.

Instead of panicking over one number, work with a functional nutritionist or provider who understands the context—including your inflammation, insulin sensitivity, diet, lifestyle, and gut health.

If you’re navigating cholesterol concerns on a low-carb or carnivore diet, I can help you understand your labs and support your health journey with science-backed strategies.

Reach out to schedule a personalized consultation.