On one side: the medically renowned Mediterranean diet, a perennial favorite among nutritionists. The competitor: the popular ketogenic diet, known for restricting carbs to precious few amounts per day.
Proponents of the ketogenic diet, also known as Keto, claim that it reduces appetite, melts belly fat, and increases mental accuracy once a person gets over the first few days of the “keto flu,” a feeling of unease, fatigue and mental confusion. Studies have also shown at least a short-term improvement in blood sugar in people following this diet.
Research has linked the Mediterranean diet to reduced risk of diabetes, high cholesterol, dementia, memory loss, depression and breast cancer, as well as weight loss, as well as ensuring stronger bones, a healthier heart and longer life.
A new controlled clinical trial done during the pandemic compared the two by asking 33 people with prediabetes or diabetes to follow the two diets, one after the other, for three months. During the first four weeks of each diet, participants were given healthy meals based on the ketogenic or Mediterranean diet and followed the meal plans on their own.
The researchers monitored the participants’ weight, blood sugar (glucose) levels, cardiovascular risk factors, and diet adherence. Which one was still prevailing in the end?
“Both diets improved blood glucose control to a similar degree, and both groups lost a similar amount of weight,” said lead nutrition researcher Walter Willett, professor of epidemiology and nutrition at the Harvard T.H. 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 the levels of blood fats that contribute to heart disease, the Mediterranean diet came out on top, according to the study published Friday in The American Journal. of Clinical Nutrition”.
The study tracked low-density lipoprotein, or LDL, known as the “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 decreased LDL cholesterol by 5%,” said Frank Hu, chair of the nutrition department at the Harvard T.H. Chan School of Public Health, who was not involved in the study.
“The difference between the two diets is quite large, and this could have long-term consequences for cardiovascular disease,” Hu said.
While both diets lowered triglycerides, the ketogenic diet did so more significantly, the study found. However, lowering triglycerides isn’t as important as raising bad cholesterol, Hu said.
“Elevated LDL cholesterol is a much more powerful and important risk factor for cardiovascular disease than triglyceride levels,” he said. “So while both sides have been quite effective in short-term glycemic control, I think the main issue is the potential long-term effects of ketogenic on cardiovascular disease.”
‘Tried to give every diet the best chance’
Ketogenic achieves rapid weight loss success, advocates say, by putting people into ketosis, a state in which the body starts burning stored fat for fuel. But to get into ketosis, carbs are drastically reduced to 20 to 50 grams per day. (A cup of cooked rice is about 50 grams). Eating additional carbs knocks you out of ketosis.
A typical American’s daily diet is 50% carbohydrate, Hu said, so dropping that intake to less than 50 grams is “a big reduction. This is hard for people to maintain.”
People often view ketogenic as a “meat” diet and fill their plates with full-fat dairy, sausage, bacon, and other meats with saturated fats, which can contribute to inflammation and chronic disease.
However, the study used a “well-formulated ketogenic diet” that limited high-protein intake and emphasized non-starchy vegetables, said study author Christopher Gardner, a professor of medicine at the Stanford Prevention Research Center.
“I tried to give each diet the best chance. I didn’t try to do a bad ketogenic and a good Mediterranean or a bad Mediterranean and a good ketogenic,” said Gardner, who is also director of the Nutrition Studies Research Group at Stanford.
The ketogenic diet bans grains, vegetables and only allows a handful of fruits. The Mediterranean diet, however, emphasizes filling your plate with fruits, vegetables, beans, lentils, whole grains, nuts and seeds.
Both 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 done to see if there’s an advantage to getting rid of fruits, whole grains and beans on ketogenic — after doing the things that everyone agrees on.”
In addition to increased bad cholesterol, people in the ketogenic phase had a “decreased intake of thiamine, vitamins B6, C, D, and E, and phosphorus,” as well as an “unbelievably low amount of fiber,” said Dr. Shivam Joshi, a clinical assistant professor of medicine at New York University’s Grossman School of Medicine. He did not participate in the study.
“Whole grains and fruits have positive health benefits, and their exclusion from the ketogenic diet group raises some concern about long-term health impacts,” Willett said. Also: “many people find long-term adherence to a ketogenic diet difficult.”
In fact, the study found that most people abandoned the keto diet after the research ended.
“They received the ketogenic food at their home. They had a health educator to help them,” Gardner said. “Still ‘boom’! Most people stopped following the ketogenic diet almost immediately. [quando essa parte do estudo terminou]while many people on the Mediterranean diet were still eating that way when the study ended.”
What is the main message of the study?
“Message #1 for me is that severe restriction of a few healthy carbohydrates is not necessary to improve glycemic control and cardiometabolic health,” said Hu.
“You can have 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.”
Source: CNN Brasil
