A new controlled clinical trial conducted during the pandemic compared the two diets asking 33 people with prediabetes or diabetes to do the two diets, one after the other, for three months. During the first four weeks of each diet, participants received deliveries of healthy keto-based or Mediterranean meals, and then followed meal plans on their own.
The researchers monitored participants ’weight, blood sugar (glucose) levels, cardiovascular risk factors, and dietary adherence. What diet was still standing in the final bell?
“Both diets improved blood glucose control to a similar degree and both groups lost a similar amount of weight,” said Dr. Walter Willett, senior nutrition researcher, professor of epidemiology and nutrition at the Harvard’s TH Chan School of Public Health and Professor of Medicine. at Harvard Medical School. He did not participate in the study.
However, when researchers examined the impact of the two diets on blood fat levels that contribute to heart disease, the Mediterranean diet was the clear winner, according to the study published Friday in The American Journal of Clinical Nutrition.
The study tracked low-density lipoprotein, or LDL, known as “bad” cholesterol, and triglycerides, which are a different type of fat in the blood that also contributes to hardening of the arteries.
“The ketogenic diet significantly increased LDL cholesterol by 10%, while the Mediterranean diet reduced LDL cholesterol by 5%,” said Dr. Frank Hu, chair of the nutrition department at Harvard TH Chan School of Public Health, which did not participate in the study.
“The difference between the two diets is quite large and this can have long-term consequences on cardiovascular disease,” Hu said.
Although both diets reduced triglycerides, the keto diet did so more significantly, the study found. However, lowering triglycerides is not as important as raising bad cholesterol, Hu said.
“High LDL cholesterol is a much more potent and important risk factor for cardiovascular disease than triglyceride levels,” he said. “So while both parts were quite effective in short-term glycemic control, I think the main problem is the potential long-term effects of keto on cardiovascular disease.”
“I tried to give each diet the best chance”
Keto achieves rapid weight loss success, advocates say, putting people in ketosis, a state in which the body begins to burn stored fat as fuel. But to achieve ketosis, carbohydrates are drastically reduced to 20 to 50 grams a day. (A cup of cooked rice is about 50 grams.) Eating extra carbs lets you out of ketosis.
A typical American’s daily diet is 50 percent carbohydrate, Hu said, so reducing that intake to less than 50 grams is “a huge reduction. It’s hard to maintain for people.” .
People often see keto as a “meat” diet and fill their dishes with dairy, sausages, bacon and other meats with saturated fats, which can contribute to inflammation and chronic disease.
However, the study used a “well-formulated ketogenic diet,” which limited high protein intake and emphasized starch-free vegetables, said study author Christopher Gardner, a research professor in medicine at Stanford Prevention Research Center.
“I tried to give the best opportunity to every diet. I didn’t try to make it a keto and a good Mediterranean or a Mediterranean and a good keto,” said Gardner, who is also the director of clinical and translational research. Stanford Diabetes Research Center area.
The keto diet prohibits any cereal, legumes and fruits except a handful of berries. The Mediterranean diet, however, emphasizes filling your dish with fruits, vegetables, beans, lentils, whole grains, nuts and seeds.
The two diets agree that “we eat too much added sugar and refined grains, and we don’t eat enough vegetables,” Gardner said. “So the whole study was set up to see if there’s an advantage to getting rid of fruits, whole grains, and keto beans, after doing the things that everyone agrees on.”
In addition to the rise in bad cholesterol, people in the ketogenic phase had “a reduced intake of thiamine, vitamins B6, C, D and E and phosphorus,” as well as an “incredibly low amount of fiber,” he said. Dr. Shivam. Joshi, assistant clinical professor of medicine at Grossman School of Medicine at New York University. He did not participate 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 impacts on health,” Willett said. In addition, he said, “A lot of people find that long-term adherence to a keto diet is difficult.”
In fact, the study found that most people quit the keto diet after completing the research.
“They delivered keto to their home. They had a health educator to help them,” Gardner said. Still, boom! Most people stopped following the keto diet almost immediately (when they finished this part of the study), while many of those doing the Mediterranean diet were still eating like that when they finished the keto diet. ‘study’.
What is the key message of the study?
“The number one message for me is that severe restriction of some healthy carbohydrates is not necessary to improve glycemic control and cardiometabolic health,” Hu said.
“You can do a healthy Mediterranean diet or a moderate low carb diet or a very healthy vegetarian diet. There are different options for people with different food preferences.”