The ketogenic diet requires the consumption of a copious amount of fat to generate the energy our body needs.

Naturally, many people on the keto diet are concerned about their cholesterol levels.

For a long time, high cholesterol levels were considered as dangerous for cardiovascular health. However, the medical community reversed this opinion and now states that cholesterol is an important building block that keeps our body functioning. A test measuring cholesterol levels in the blood is called blood lipid profile.

When talking about it is important to look at what the term “cholesterol” means.

What is Cholesterol, and how is it measured?

Cholesterol is a waxy substance that is essential for bodily functions, cell health, and integrity and the generation of new cells.

Our liver produces about 75% of the cholesterol; roughly 25% comes from food.

There are three types of lipoproteins that make up the pool summarily called “cholesterol.”

• Low-Density Lipoproteins
• High-Density Lipoproteins
• Triglycerides

Low-Density Lipoproteins:

The first component is the Low-Density Lipoprotein or LDL in short. LDL is the “bad” cholesterol that contributes to the waxy build-up in arteries. This buildup occurs inside the walls of blood vessels and, over time, causes a narrowing of these arteries, also called arteriosclerosis.

Global and US-based health guidelines determine that 100 mg/dL or less LDL in healthy people significantly reduces the risk of developing cardiovascular diseases and stroke. If your level is higher than 160 mg/dL, your risk is very high, and the LDL levels must be reduced either through diet or drugs called statins.

High-Density Lipoproteins (HDL):

In contrast to LDL, HDL is called “good cholesterol.” High levels of HDL significantly lower an individual’s risk for cardiovascular diseases, metabolic diseases, and stroke. HDL protects you by removing LDL from your blood, thus preventing it from sticking to the artery walls and create the dangerous waxy buildup leading to arteriosclerosis. 

Certain statins, but also Niacin can increase your HDL levels. Also, proper diet low on carbohydrates, saturated and trans fats, and regular exercise are natural inducers of HDL.

Triglycerides:

Triglycerides store excessive energy created by overconsumption of food and make up most of the fat stored in our body.  

A triglyceride is composed of three molecules of fat and one molecule of the alcohol glycerol. The major source for triglycerides in food is fat from natural oils, animal fats, trans fats, and triglycerides. Specifically, trans fats such as margarine and saturated fats in red meat, bacon and poultry skin can increase triglyceride levels. In contrast, unsaturated fats found in olive oil, avocados, nuts and low-fat products contribute less to a rise of triglyceride levels in the blood. Another significant source for the generation of triglycerides in our body are simple, refined carbohydrates such as sugars and excessive consumption of alcohol.

We have identified LDL, HDL, and Triglycerides as main components of blood cholesterol. In general, there is a rightful fear of “high cholesterol.”

What are healthy cholesterol levels?

When we are talking about “high cholesterol,” it is important to know two terms:

1. Hyperlipidemia: Your blood has too many lipids, cholesterol, and triglycerides.

Hyperlipidemia can have dietary and genetic origins. A sensible diet low on saturated fats and high on unsaturated fats can help to reduce the risks of hyperlipidemia and total cholesterol. In genetic hyperlipidemia, dietary restrictions are unlikely to help; your physician might prescribe drugs called statins.

• Hypercholesterolemia: Your blood has too much LDL (bad cholesterol) and too little HDL (good cholesterol). Here the ratio of LDL to HDL is important.

The blood cholesterol levels are measured in total cholesterol, and HDL and LDL. Since HDL is the only “good” cholesterol, the ratio of total cholesterol, or non-HDL cholesterol, to HDL is a better indicator for hypercholesterolemia and associated health risks.

The calculation of this ratio is simple:

Total cholesterol divided by HDL level

Ideally, this ratio should be less than 4

Another way to measure cholesterol levels is the difference between total cholesterol and non-HDL cholesterol:

Total Cholesterol minus HDL = Non-HDL Cholesterol

Ideally NON-HDL cholesterol level should be less than 130 mg/dL

This calculation is considered to be more accurate as it accounts for a partially “bad” version of LDL, the Very Low-Density Lipoprotein, or VLDL. LDL carries cholesterol, while VLDL carries triglycerides in our bloodstream to each cell in our body.

Ideally, your VLDL should be one-fifth of your triglyceride levels, or about 30 mg/dL or less.

VLDL, like its cousin LDL, can create the build up inside of blood vessels (atherosclerosis) but is stickier and, therefore more resistant to removal by the good HDL.

Since VLDL are carriers of triglycerides, their levels in the blood are linked. Lowering the triglycerides will lower VLDL.

A natural way of lowering triglycerides and VLDL is regular exercise, weight loss, consumption of healthy fats, and a significant reduction in the consumption of carbohydrates and alcohol.

In summary, a healthy lifestyle targeting lowering “cholesterol” levels should target the reduction of bad LDL, VLDL and triglycerides, and an increase of HDL.

Effect of Keto Diet on Cholesterol Levels:

After explaining what “cholesterol levels” mean, let’s get back to the question of whether the Keto Diet can negatively affect your blood cholesterol levels?

Anything done wrong can affect your health, so can a wrong Keto Diet. Let’s look at the daily nutritional allowances for macronutrients of this diet:

• FAT: 55-60%
• PROTEIN: 30-35 %
• CARBOHYDRATES: 5-10%

Science is divided whether the Keto Diet increases or decreases the bad cholesterol LDL and VLDL. One study reports an overall decrease of LDL while other studies show an increase of LDL and VLDL levels. Interestingly, a long-term study of a genetic deficiency called Glut 1D, which is treated effectively with high fat and low carbohydrate diet, did show a reduction of LDL, HDL, triglyceride, and total cholesterol levels. At the same time, the Keto Diet used to treat this deficiency did improve non-cholesterol to HDL ratio to a healthy level.

A study published in 2014 found that a low-carb diet is more effective than a low-fat diet for reducing the risk of cardiovascular risks.

In another study, participants of a Keto Diet study lost an average of 7.7 pounds within 12 months more than participants following a low-fat diet. Besides, there is further scientific evidence that low-carb and high-fat diet does not increase cardiovascular risk while facilitating weight-loss.

In summary, there is no evidence that the Keto Diet increases cardiovascular risk by elevating blood cholesterol levels.

The American Heart Association (AHA), a worldwide authority in cardiovascular disease, emphasizes the importance of a healthy lifestyle without endorsing a diet. Moreover, in contrast to their earlier position, the AHA does no longer support a low-fat diet but recommends a diet moderate in healthy, unsaturated fats and low in sugars and refined carbohydrates.  Nevertheless, without endorsing the Keto Diet, AHA published success stories of people following this diet.

However, to be healthy individuals participating in the Keto Diet must follow certain guidelines and consult with their physician before starting.

Here are a few recommendations for participants of the Keto Diet:

1. Know your fats: Saturated fats found in butter, animal fat, coconut are less healthy than unsaturated fats found in nuts, olive oil, vegetable oil, plant seed oil, and avocado. Consume more unsaturated fats than saturated fats. If you insist on Coconut oil, make sure it contains 100% of medium-chain triglycerides (MCT). Regular coconut oil contains only 13 to 14 % of MCT and up to 86% of unhealthy saturated fat.
2. Reduce carbohydrate intake from all food sources to less than 20 g/day (10%).
3. Reduce your food consumption in general, limiting daily calorie intake to 2000 calories a day.
4. Increase fiber intake through keto vegetables to avoid constipation, and digestive problems frequently observed in the Keto Diet. In general, root vegetables such as potatoes, carrots, and celery contain more calories than leaf vegetables, such as spinach, zucchini, lettuce, and asparagus.
5. Exercise regularly to burn off any unnecessary calories, either from fat or from carbohydrates. Remember that excessive calories from fat can cause weight gain, too.
6. Consult your physician before starting the Keto Diet and have your health monitored regularly. Remember that people with a genetic predisposition to high cholesterol or LDL levels and metabolic disorders should avoid Keto Diet, as their body is unable to reduce the bad cholesterol in general.

In summary, while there is no conclusive scientific evidence that Keto Diet increases bad cholesterol levels, many single studies show a decrease in cardiovascular risks and generally improved health conditions.

Learn more about Cholesterol in this short video by the American Heart Association.