The ketogenic diet is generally healthful for most people and can even help lower cholesterol levels in the long term. However, some people may need to adjust their keto diet to avoid raising their cholesterol levels.

Q: Will a keto diet affect my already high cholesterol?

The keto diet, short for ketogenic diet, is a popular diet that people use to lose weight and improve their overall health and well-being.

It involves restricting your total carbohydrate intake to 20–50 grams per day, which forces your body to shift from using glucose — a type of sugar — as its main source of energy to using ketone bodies, a type of chemical formed from the breakdown of fat (1).

When this transition happens, your body enters a natural metabolic state known as ketosis (2).

Generally speaking, a keto diet is healthy, safe, and suitable for most people, though more research into the long-term effects is needed (3).

The keto diet is likely not the best option for you if you have kidney disease, liver diseases, familial hypercholesterolemia (high cholesterol levels inherited from family), or fat-induced lipemia, because the diet may worsen these conditions.

If you have type 1 diabetes, gallbladder issues, or a genetic disorder that influences fat metabolism, consult a dietitian before adopting a keto diet (4).

Animal studies have suggested that a keto diet may result in changes in fetal growth and increase anxiety and depression in adulthood (5, 6).

The diet can also make it more difficult to get enough of certain nutrients. More research is needed to determine whether the keto diet is safe during pregnancy.

If you have high cholesterol levels and are interested in trying the keto diet, it’s important to ask a healthcare professional whether the diet is suitable for you, based on your particular cholesterol levels and overall health.

Most research suggests that keto diets can help lower total cholesterol and LDL (bad) cholesterol levels while raising HDL (good) cholesterol levels.

In some cases, the keto diet may raise total and LDL cholesterol levels higher in the short term. However, research suggests that both total and LDL cholesterol levels fall in the long term, while HDL cholesterol levels appear to rise (7, 8, 9).

If you have preexisting high cholesterol levels, you’ll need to adjust the structure of your keto diet to prevent it from raising your cholesterol levels.

For starters, consider avoiding artificial trans fats, processed meats, and fried foods, as these foods may raise your risk of heart disease (10, 11).

You might also consider replacing some of the saturated fats in the diet with monounsaturated fats. Although saturated fats aren’t unhealthy, swapping them for monounsaturated fats may help lower your cholesterol levels (12).

Avocados, olive oil, nuts, and nut butters are good sources of monounsaturated fats.

In addition, certain polyunsaturated fats, such as omega-3 fats, may help lower triglyceride levels and increase HDL (good) cholesterol when consumed on a keto diet. Flax seeds, chia seeds, walnuts, and fatty fish such as salmon are good sources of omega-3s (13).

Lastly, just because a keto diet is low carb doesn’t mean it should be low fiber. Consider including fiber-rich foods such as nuts, seeds, berries, and low carb veggies, as a higher fiber intake may help lower your cholesterol levels (14, 15).