In the 1950s, researchers from around the world embarked on a large and ambitious study. For decades, they analyzed the diets and lifestyles of thousands of middle-aged men living in the United States, Europe and Japan, and then examined how those characteristics affected the risk of developing cardiovascular disease.
The seven-country study, as it later became known, found associations between saturated fat, cholesterol levels, and coronary heart disease. But the researchers also got another remarkable result: People living in and around the Mediterranean — in countries like Italy, Greece, and Croatia — had lower rates of cardiovascular disease than those living elsewhere. Their diets, rich in fruits, vegetables, legumes, whole grains, nuts, seeds, lean protein, and healthy fats, appeared to have a protective effect.
Since then, the Mediterranean diet has become the cornerstone of a heart-healthy diet, with well-studied health benefits such as lowering blood pressure and cholesterol, as well as a reduced risk of type 2 diabetes.
“It’s one of the few diets that has studies to back it up,” said Sean Heffron, a preventive cardiologist at NYU Langone Health. “It is not a diet that someone came up with to make money. It’s something that millions of people have developed over time because it actually tastes good. And, in addition, it turns out that it is healthy”, added the specialist. Here are the expert answers to some of the most frequently asked questions about the Mediterranean diet.
What exactly is the Mediterranean diet?
The Mediterranean diet isn’t so much a strict eating regimen as more of a lifestyle, says Julia Zumpano, a registered dietitian specializing in preventive cardiology at Ohio’s Cleveland Clinic. People who follow the Mediterranean diet tend to “eat foods that your grandparents would recognize,” Heffron added: whole foods, unprocessed and with few or no additives.
The diet gives priority to whole grains, fruits, vegetables, legumes, nuts, herbs, spices and olive oil. Fish rich in omega-3 fatty acids, such as salmon, sardines, and tuna, is the preferred source of animal protein. Other lean animal proteins, such as chicken or turkey, are consumed in smaller amounts. And foods high in saturated fat, such as red meat and butter, are rarely eaten. Eggs and dairy products like yogurt and cheese can also be part of the Mediterranean diet, but in moderation. And a moderate consumption of alcohol is allowed, such as a glass of wine at dinner.
Breakfast can be a smashed avocado on whole-wheat toast accompanied by fresh fruit and low-fat yogurt, Heffron said. For lunch or dinner, a vegetable or grain dish cooked in olive oil and seasoned with herbs: roasted root vegetables, leafy greens, a side of hummus, and small portions of pasta or whole wheat bread, with a lean protein such as fish grilled. “It’s very easy to follow, very sustainable and very realistic,” says Zumpano.
What are the health benefits of the Mediterranean diet?
Various rigorous studies have found that the Mediterranean diet contributes to better health, and particularly heart health, in different ways. In one study, published in 2018, researchers evaluated nearly 26,000 women and found that those who most closely followed the Mediterranean diet for up to 12 years had around a 25 percent lower risk of developing cardiovascular disease. This was primarily due to changes in blood glucose, inflammation and body mass index, the researchers reported. Other studies, conducted on men and women, have reached similar conclusions.
Research has also found that diet can protect against oxidative stress, which can cause DNA damage that contributes to chronic conditions such as neurological disease and cancer. And some studies suggest that it may help reduce the risk of developing type 2 diabetes.
According to Anum Sohail Minhas, Associate Professor of Medicine at Johns Hopkins Medicine, diet can also be very beneficial to health during pregnancy. In a recent study of nearly 7,800 women published in December, researchers found that women who followed the Mediterranean diet more closely around the time of conception and during the first few months of pregnancy had a 21 percent lower risk of complications such as preeclampsia, gestational diabetes, or preterm labor. “Ultimately, there seems to be a protective effect,” Minhas said.
However, Heffron explains that the Mediterranean diet, by itself, is not a panacea: it will not eliminate the chances of developing cardiovascular diseases nor will it cure them. It’s important to pay attention to other principles of good heart health, such as exercising regularly, getting enough sleep, and not smoking.
Does the Mediterranean diet help to lose weight?
According to Zumpano, this diet can promote weight loss, but you have to pay attention to calories. “Nutrient-dense foods aren’t necessarily low-calorie,” said Heffron, noting that the diet includes foods like olive oil and nuts, which are good for the heart but are high in calories and can cause an increase in weight if consumed in large quantities, adding that if you are changing your diet from one that is high in calories, saturated fat, and added sugars, to one that places more emphasis on vegetables, fruits, and leaner proteins, you can lose some weight.
However, the Mediterranean diet is not a shortcut to losing weight quickly. Rather, it should be inspiration to change behavior in the long term. In a study of more than 30,000 people in Italy, for example, researchers found that those who followed the Mediterranean diet more closely for 12 years were less likely to be overweight or obese than those who followed the diet less. A smaller study, published in 2020, included 565 adult participants who had intentionally lost 10 percent or more of their body weight in the previous year and found that those who reported following the Mediterranean diet more closely were twice as likely in maintaining weight loss than those who did not follow it as closely.
How long do you need to follow the Mediterranean diet to get benefits?
If you’ve just started following the Mediterranean diet, there is limited evidence to suggest that you may notice some cognitive improvements (such as attention, alertness, and satisfaction, according to a review of studies published in 2021) within the first 10 days more or less. However, Zumpano says that to get sustained, long-term benefits in terms of heart health, you need to stick to the diet for a lifetime. That said, he added, the diet allows for some flexibility; an occasional pie or steak will not negate your overall benefits.
Does following this diet have any disadvantages?
The diet typically provides a balanced mix of nutrients and adequate protein, so there are usually no significant risks associated with following it, Heffron said. But since the diet recommends minimizing or avoiding red meat, you may want to make sure you get enough iron. Good sources of iron include nuts, tofu, legumes, and dark green leafy vegetables, such as spinach and broccoli. Foods rich in vitamin C, such as citrus fruits, bell peppers, strawberries, and tomatoes, can also help the body absorb iron. And since the diet minimizes dairy, you may want to talk to your doctor about whether you need to take a calcium supplement. However, for the average person, the benefits of the Mediterranean diet far outweigh the potential negative effects, Minhas says. “These are things that we can all try to incorporate into our lives,” he said.
