What Is the Mediterranean Diet?

In the 1950s, a team of researchers around the world began looking at thousands of middle-aged men (40 to 59 years old) living in seven countries — Finland, Greece, Italy, Japan, Netherlands, United States and the former Yugoslavia — to see how their diets and lifestyles affected their risk of cardiovascular disease, which had suddenly become the leading cause of death in the U.S.

The seminal Seven Countries Study, as it later became known, showed that serum cholesterol, blood pressure, diabetes and smoking are universal risk factors for coronary heart disease. But that wasn’t the only finding.

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The researchers also noticed something unusual about the people who lived in the countries surrounding the Mediterranean Sea: They were healthier than people in wealthier Western nations; specifically, they had lower rates of chronic disease and a higher-than-average life expectancy, despite their limited access to health care.

As they began investigating the potential reasons, most, if not all, arrows pointed to diet. People living in the Mediterranean countries didn’t eat exactly the same foods, but they did all eat, for the most part, a plant-based diet. And that diet seemed to have a protective effect on heart health and longevity.

In 1960, Ancel Keys, the American physiologist who launched the Seven Countries Study, coined what’s now known as the “Mediterranean diet.”

What foods are allowed on the Mediterranean diet?

The name is slightly misleading because it refers to more of a dietary pattern — of which there are slight variations — rather than a single regimented diet.

What all versions have in common, however, is an emphasis on a variety of fruits, vegetables, whole grains, beans, nuts, legumes, fish (especially those rich in omega-3 fatty acids such as salmon, sardines and mackerel) and healthy fats like olive oil. Eggs and dairy products are OK, but only in moderation. The same goes for alcohol. Up to a glass of wine at dinner is given a green light on the Mediterranean plan.

“There is no single definition for a Mediterranean diet, since it encompasses the eating pattern of all 16 countries that border the Mediterranean Sea, including parts of Europe, Asia and Africa,” explains Liz Weinandy, an outpatient dietitian and clinical instructor at the Ohio State University Wexner Medical Center. “It’s healthy for anyone of any age who’s looking to follow an overall healthy eating plan that benefits every part of the body.”

But following the Mediterranean diet involves more than simply eating a checklist of foods. Lifestyle plays an equally important role, too. Specifically, eating fresh in-season produce, sitting down to meals with family and or friends, and staying physically active by doing something you enjoy (playing pickleball, for instance, or going for a swim or a long walk outdoors) as opposed to something you don’t (like, say, logging steps on the treadmill or minutes on the elliptical machine).