In one corner: the medically renowned Mediterranean diet, a  favorite among doctors and nutritionists. The contender: the popular keto diet, known for restricting carbohydrates to a few per day. Which is better?

When researchers examined the impact of the two diets on levels of blood fats that contribute to heart disease, the Mediterranean diet was the clear winner, according to The American Journal of Clinical Nutrition.

Long life comes from eating right

Keto proponents claim their diet reduces appetite, melts abdominal fat and boosts mental sharpness, especially once a person is over the first few days of “keto flu,” which is a feeling of fatigue and brain fog.  Studies do show that at least in the short term a reduction in blood sugar in people who are on keto.

Research has linked the Mediterranean diet to reduced risk for diabetes, high cholesterol, dementia, memory loss, depression and breast cancer as well as weight loss, stronger bones, a healthier heart and longer life.

A controlled clinical trial done during the pandemic compared the two diets

The study asked 33 people with pre-diabetes or diabetes to do both diets, one after the other, for three months. During the first four weeks of each diet, participants received either healthy keto- or Mediterranean-based meal deliveries, they then followed meal plans on their own.

Researchers monitored participants’ weight, blood sugar (glucose) levels, cardiovascular risk factors and adherence to the diet. Which diet was still standing at the final bell?

“Both diets improved blood glucose control to a similar degree, and both groups lost a similar amount of weight,” said leading nutrition researcher Dr. Walter Willett, a professor of epidemiology and nutrition at Harvard T.H. Chan School of Public Health and professor of medicine at Harvard Medical School who not involved in the study.

However, when researchers examined the impact of the two diets on levels of blood fats that contribute to heart disease, the Mediterranean diet was the clear winner, according to The American Journal of Clinical Nutrition.

LDL and the link to heart disease

The study tracked low-density lipoprotein, or LDL, known as the “bad” cholesterol, and triglycerides, which are the type of fat in the blood that contributes to hardening of the arteries.

“The keto diet significantly increased LDL cholesterol by 10%, while the Mediterranean diet decreased LDL cholesterol by 5%. The difference between the two diets is quite large, and this may have long-term consequences on cardiovascular disease,” said Dr. Frank Hu of the Harvard Chan School of Public Health.

While both diets reduced triglycerides, the keto diet did so more significantly, the study found. However, the reduction in triglycerides is not as important as the rise in bad cholesterol, Hu said.

“High LDL cholesterol is a much more powerful and important risk factor for cardiovascular disease than triglyceride levels,” he said. “So while both sides were quite effective in short-term glycemic control, I think the main issue is the potential long-term effects of keto on cardiovascular disease.”

‘I tried to give each diet the best chance’

“I tried to give each diet the best chance. I didn’t try to make it a crappy keto and a good Mediterranean or a crappy Mediterranean and a good keto,” said Gardner, who is also the director of the Nutrition Studies Research Group at Stanford.

People often view keto as a “meat” diet and fill their plates with full-fat dairy, sausage, bacon and other meats with saturated fats, all of which can contribute to inflammation and chronic disease. However, the study used a “well-formulated ketogenic diet,” which limited high protein intake and emphasized non-starchy vegetables, said study author Christopher Gardner.

A typical American’s daily diet is 50% carbohydrates, Hu said, so decreasing that intake to less than 50 grams is “a huge reduction. That’s tough for people to maintain.”

The keto diet bans any grains, legumes and fruits except for a handful of berries. The Mediterranean diet, however, emphasizes packing your plate with fruits, vegetables, beans, lentils, whole grains, nuts and seeds.

How to start the Mediterranean diet — meal by meal

Both diets agree that we eat way too much added sugar and refined grains, and we don’t eat enough vegetables

“So the whole study was set up to see if there is an advantage to getting rid of fruits, whole grains and beans on keto .” said Gardner author of the study.

In addition to the rise in bad cholesterol, people on the keto phase had a “decreased intake of thiamine, vitamins B6, C, D and E, and phosphorus” as well as an “incredibly low amount of fiber,” said Dr. Shivam Joshi, a clinical assistant professor of medicine at New York University Grossman School of Medicine. He was not involved in the study.

“Whole grains and fruits have positive health benefits, and their exclusion from the keto group raises some concern about the long-term health impacts. In addition, Many people find that long-term adherence to a keto diet is difficult.”

Indeed, the study found that most people dropped the keto diet after the research ended.

“They had keto delivered to their house. They had a health educator help them,” Gardner said. “Yet boom! Most people quit following the keto diet almost immediately (when that portion of the study ended), while many of those on the Mediterranean diet were still eating that way when the study was over.”

What is the key message of the study?

The No. 1 take-home message is that severe restriction of some healthy carbohydrates is not necessary to improve glycemic control and cardio metabolic health,” Hu said.

“You can do a healthy Mediterranean diet or a moderate low-carbohydrate diet or a very healthy vegetarian diet. There are different options for people with different food preferences.”

Source: https://www.cnn.com/2022/07/08/health/keto-mediterranean-diet-showdown/index.html