At Harvard Medical School, a group of researchers decided to test a bold theory on their own bodies. For many years, they were on a strict keto diet, which almost completely eliminates carbohydrates from the diet and is based on a high intake of fat. Such a diet has positive effects for many, especially for people with autoimmune issues such as ulcerative colitis (a disease where the intestinal lining becomes inflamed, causing pain and digestive issues). The keto diet is very helpful for most, but...

When they started, all the participants had the same issue: very high LDL cholesterol. And we're not talking about just a slight increase. Levels of their bad cholesterol (LDL) were at 14 mmol/L, which is almost five times above the recommended upper limit.

What is cholesterol and why is it important?

Cholesterol is a waxy substance found in the blood that is essential for cell and hormone production. It is divided into LDL (bad cholesterol), which accumulates on the walls of blood vessels, and HDL (good cholesterol), which helps remove excess cholesterol from the body.

According to the World Health Organization, a healthy adult should have LDL values below 3 mmol/L. In Europe, high cholesterol affects 58% of adults, which is concerning as it is a major risk factor for heart diseases.

Where do Oreo cookies come into the story?

Researchers asked the question: What if high cholesterol levels are not just a result of fat in the diet but also a lack of carbohydrates?

To test this theory, volunteers consumed 12 Oreo cookies a day for 16 days, which is approximately 100 grams of carbohydrates. The rest of the diet remained unchanged, following the rules of LCHF. Simultaneously, the volunteers took a dietary supplement of D-beta-hydroxybutyrate, which may sound like a magical herbal ingredient, but in reality, it helps the body maintain ketosis, a state where the body uses fats for energy instead of sugars.

What was the result?

After just over two weeks, cholesterol decreased by 71% (from 14 to 2.9 mmol/L). This is a turnaround that many users of cholesterol-lowering medications would dream of!

What do scientific explanations say?

There are several theories as to why this happens. One of the most well-known is the lipid energy model. To simplify: when the body lacks sugars (carbohydrates), it depletes glycogen stores (sugars stored in the liver), leading to the breakdown of fats for energy. This process triggers increased production of cholesterol, especially the bad kind.

However, once the body receives carbohydrates again, even from sweet cookies, glycogen stores are replenished, eliminating the need for the body to breakdown fats for energy in such an intense manner. As a result, cholesterol production decreases.

This is an intriguing hypothesis supported by many nutritionists. In the journal Metabolites, they noted similar occurrences in people with low body mass index (BMI). In such individuals, a strict ketogenic diet could lead to a dramatic increase in cholesterol.

After the cookie trial phase, the participants returned to a classic ketogenic diet for three months to cleanse the body. This was followed by a trial of cholesterol-lowering medications, specifically rosuvastatin at a dose of 20 mg daily.

And how successful was it?

The medication reduced LDL cholesterol by 32.5% - which is almost half the reduction achieved by Oreo cookies.

Of course, these results are not an advertisement to start eating industrial cookies, but a reminder that the body is a very sensitive system where dietary changes can quickly affect hormones, metabolism, and blood profiles.

Could similar results be achieved with other foods?

Very likely. Although Oreo cookies are full of sugar, white oil, and artificial flavors, researchers acknowledged that a similar effect could be achieved with a banana, a slice of bread, or a boiled potato. This means that carbohydrates that help lower LDL cholesterol can also be obtained from natural foods.

A ripe banana, for example, contains 27 grams of carbohydrates, mostly in the form of natural fruit sugar that slowly releases into the bloodstream. A full plate of boiled potatoes has 30 grams of carbohydrates, along with potassium that lowers blood pressure.

What can we learn from this?

If you have high cholesterol and are following a ketogenic diet, it may be time for reflection. In a study published in the Journal of Clinical Lipidology, 20% of people on a keto diet experienced a significant increase in LDL cholesterol, regardless of overall weight loss. Interestingly, these were mostly younger, lean individuals.

It is also important to emphasize that the long-term effects of consuming refined carbohydrates, like sugar and white flour, are harmful. They increase the risk of diabetes, cardiovascular diseases, and even some forms of cancer. Therefore, this story is primarily a reminder that the body needs balance and that too much fat without carbohydrates can upset this balance.

What does traditional medicine say?

Our grandparents also knew that excess is not good - neither with meat nor with fat. They recognized the power of barley porridge, dried fruit, honey, chestnut flour, and even salty soups as regulators of the body. Traditional medicine has always aimed for balance - a principle that science has rediscovered today.

While the story about Oreo cookies may sound like a tabloid headline, it is backed by science that opens the doors to a better understanding of how diet affects cholesterol. It's not an advertisement for cookies but an important lesson: even natural carbohydrates play a role in diet - and they can even help in cholesterol management for individuals on a ketogenic diet.