Does the keto diet affect cholesterol?
- fat: 55–60% of the day's total macronutrients
- protein: 30–35%
- carbohydrates: 5–10%
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?
Eating a keto diet may affect cholesterol levels.
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.
Risks of the keto diet
A person on a keto diet may experience headaches, weakness, and muscle cramps.
Some people following the keto diet may experience:
The keto flu is a collection of minor, short term symptoms that some people experience when they start the keto diet. These symptoms include:
- difficulty tolerating exercise
Several studies have suggested that the keto diet can affect cholesterol levels.
When people consume low amounts of carbohydrates, the liver produces fewer triglycerides, which may be involved in raising HDL cholesterol levels.
However, the keto diet may raise LDL cholesterol levels in some people. As a result, the diet may not be appropriate for everyone.
It may not be suitable, for example, for people with fat induced lipemia. This condition leads to very high levels of fat in the blood.
If a person with fat induced lipemia follows the keto diet, their triglyceride levels may continue to rise, which may result in pancreatitis. Generally, people with lipemia must follow a low fat diet.
People who want to lose weight should speak with a doctor to identify a suitable diet.
When considering recommending the keto diet, doctors must weigh the risks with the potential benefits, which can include rapid weight loss, reduced triglyceride levels, and increased HDL cholesterol levels.
The importance of ongoing monitoring
People who follow the keto diet should consult their doctors to arrange frequent monitoring of blood cholesterol and triglyceride levels.
If a doctor notices that LDL cholesterol levels are rising, the diet may no longer be appropriate.
People with high levels of fats, such as cholesterol and triglycerides, in their blood have an increased risk of developing cardiovascular disease.
Foods to eat and avoid
A person on a keto diet should try to drink low fat milks.
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.
Fish — such as salmon, tuna, and cod — can be an excellent source of protein, and they contain unsaturated fat, such as omega-3 fatty acids, which can be beneficial for the body.
People with high cholesterol who follow the keto diet can snack on certain nuts and seeds that are generally low in carbs and rich in fiber and protein. Chia seeds have a higher content of polyunsaturated fats.
Vegetables, fruits, and legumes are excellent sources of nutrition. However, anyone following the keto diet should be aware of the carbohydrate contents of these foods.
People on the keto diet can consume milk and products containing it, but they may want to choose low fat versions if they have high cholesterol.
Some studies suggest that following the keto diet is an effective and rapid way to lose weight.
However, people may find the keto diet difficult to follow. In this case, they may wish to consult a doctor or dietitian.
Studies have indicated that the keto diet results in significant weight loss among people with obesity. However, researchers must study the diet further to determine the long term health consequences.