Why does veganism still increase cholesterol?

Experts say the calorie difference between a vegan diet and a meat-based keto diet can increase bad cholesterol.

Nick Norwitz, 25, a medical student at Harvard University, experimented with a vegan diet for a week and recorded his health indicators. He had previously tried a meat-only keto diet for comparison.

The study, published in mid-November, found that his LDL cholesterol had increased, contradicting the commonly known health benefits of the diet. Low-density lipoprotein (LDL) , often referred to as 'bad cholesterol ,' can be harmful to health at high levels.

His vegan diet focuses on tofu, vegan protein powder, greens like spinach and kale, some dark chocolate and macadamia nut butter. His main sources of fat include macadamia oil, extra virgin olive oil and roasted sesame oil.

Norwitz shares the specific nutrient amounts he consumes on both diets in his video. 'My stomach gets pretty upset on the vegan diet. It's just how my body and my gut microbiome react,' Norwitz says.

Despite eating less total fat and saturated fat and more fiber, his LDL cholesterol still increased. The reason is the difference in calories on the vegan keto diet and the all-meat keto diet.

The carnivore diet, also known as the ketogenic diet, is a variation of the ketogenic diet in which the dieter primarily consumes meats and animal products, while limiting or completely eliminating plant-based carbohydrates.

On a diet that's almost entirely meat-based, Norwitz consumes 3,479 calories per day, which is about the same as maintaining his weight. Meanwhile, on a vegan keto diet, he consumes just 2,054 calories per day, which is significantly less.

The sudden drop in calories caused him to lose weight. Norwitz lost about 4 pounds while on the vegan diet, which he believes is the reason for the spike in LDL. Previous studies have shown an inverse relationship between LDL cholesterol and body mass index (BMI) on low-carb diets.

In addition, consuming too much saturated fat from plants such as coconut oil, palm oil and products made from them can increase LDL cholesterol levels.

Cholesterol test. (Photo: iStock).

'The analysis showed that people with a BMI under 25 tended to have elevated LDL. The leaner the person, the higher the LDL, all other things being equal,' he explains. Norwitz detailed the scientific reasons for this link. He believes the results could apply to other lean, active people on a low-carb diet in a controlled environment .

' People can live well on a vegan diet, but veganism is not essential for health,' says Norwitz.

Norwitz hopes his experiment will inspire people to learn more about their own metabolic health.

Dr. Bradley Serwer, cardiologist and medical director of VitalSolution, says that foods that are 'labeled vegan' are not necessarily healthy. He says it's important to limit processed foods and refined carbohydrates (sugar), which are often found in many vegan products. Genetics also play a role in how people metabolize cholesterol.

Dr. Serwer says that sudden changes in diet can disrupt the body's physiology and cause fluctuations in cholesterol levels. People who choose to go vegan should increase their soluble fiber intake, focus on whole, minimally processed foods, and add healthy fats like avocados, nuts, seeds, and olive oil to their diet.