Does the keto diet affect cholesterol?

People who follow the ketogenic, or keto, diet eat high amounts of fat, moderate amounts of protein, and minimal amounts of carbohydrates. Some evidence suggests that following this diet can affect cholesterol levels.

Some studies suggest that the keto diet can lower levels of high density lipoprotein (HDL), or "good," cholesterol but raise levels of low density lipoprotein (LDL), or "bad," cholesterol. For this reason, the keto diet may not be appropriate for everyone.

For example, healthcare professionals may advise that people with high cholesterol do not follow the keto diet.

In this article, learn more about the keto diet and its effects on cholesterol. We also describe safety considerations.

What does the research say?

An older study in the Annals of Internal Medicine divided participants into a keto diet group and a low fat diet group.

Throughout the study, people in both groups lost more fat mass than fat free mass. Their LDL cholesterol levels did not change, however.

Those in the keto diet group lost more weight, had more significant reductions in triglyceride levels, and had higher HDL cholesterol levels. HDL levels tend to rise when people replace carbohydrates with saturated, monounsaturated, and polyunsaturated fats.

It is important to note that the researchers only followed the participants for 6 months. As a result, it is not clear whether or how their cholesterol levels changed later on.

The authors mention that in previous studies, researchers have found conflicting results.

For example, they refer to one study in which participants who had followed the keto diet for 2 months experienced an average rise in LDL cholesterol levels of 0.62 millimoles per liter (mmol/L). Another study showed a decrease of 0.26 mmol/L in LDL cholesterol levels after 6 months.

A further study monitored people who had followed either the keto diet or a low fat diet for 1 year.

This was a follow-up study to a previous project. The results of the earlier study had suggested that the keto diet leads to more weight loss and healthier cholesterol levels in people with obesity after 6 months.

The researchers note that after 1 year, participants following the keto diet still had lower triglyceride levels and higher HDL cholesterol levels than those following the low fat diet. They also found that people in both groups lost the same amount of weight, on average.

However, given that all the participants in these studies had obesity, the results may not apply to people without it.

More recent research has continued to arrive at conflicting results. Research from 2016 observed a rise in LDL cholesterol and a decrease in HDL cholesterol linked with the keto diet.

A paper from 2018 reports the opposite, suggesting that the keto diet could raise HDL cholesterol levels.

People with high cholesterol should adopt a lifestyle that reduces these levels. This is because high cholesterol is associated with cardiovascular disease.

The keto diet emphasizes high amounts of fat, but not all fats have equal value. For example, replacing saturated fats with unsaturated fats is associated with a lower risk of cardiovascular disease, according to the 2015–2020 Dietary Guidelines for Americans.

Saturated fats occur in foods such as cookies, cakes, and other snacks. Coconut oil, butter, and ghee contain high levels of saturated fats, whereas extra virgin olive oil and margarine are higher in monounsaturated and polyunsaturated fats.