The Mediterranean diet as we know it today is based broadly on the diet of the countries lining the Mediterranean Sea. It became a phenomenon around the world when, in the 1950s and '60s, Ancel Keys and his colleagues studied the diets and overall health of seven countries (United States, the Netherlands, Finland, Yugoslavia, Italy, Greece, and Japan) in relation to coronary heart disease risk. They found that people in Italy and Greece had the lowest risk of developing coronary heart disease, partially due to their diet.

So what exactly does the Mediterranean diet look like? Unlike diets like paleo and keto, it does not limit macros or calories or cut out any particular food groups (such as grains). Instead, it focuses more on a healthy pattern of eating real, whole foods within every food group—possibly making you less likely to feel restricted and more likely to stick to it.

A typical, balanced Mediterranean diet includes antioxidant-rich fruits, vegetables, whole grains, beans, legumes, nuts, seeds, olive oil, herbs, and spices. It also promotes regular consumption of omega-3-rich fish and seafood and weekly consumption of poultry, eggs, cheese, and yogurt. The diet limits red meat, sweets, and other processed foods. Red wine is encouraged in moderation, but it's not a must. Coffee and tea are also allowed, but focus on drinking lots and lots of water.

"It's usually the diet I recommend for my diabetic, heart disease, and autoimmune patients who do not have any food allergies or intolerances," Bindiya Gandhi, M.D., an American Board Family Medicine–certified physician, told mbg.

The Mediterranean diet is also more than just a diet—it emphasizes physical activity and social relationships. So exercising (even just walking) and dining with friends regularly is also encouraged.