The Mediterranean Diet: What It Is and Why It Works

Among the countless diets that promise better health, the Mediterranean pattern stands out for one reason: it has the strongest evidence behind it. Rather than a strict set of rules, it is a way of eating built around vegetables, fruit, whole grains, legumes, nuts, fish, and olive oil, with less red meat, added sugar, and processed food.

This guide covers what the best trial actually found, what the diet looks like on a plate, and how to ease into it.

The essentials at a glance

• In a large randomized trial of people at high cardiovascular risk, a Mediterranean diet (with extra-virgin olive oil or nuts) reduced major cardiovascular events versus a low-fat control, roughly a 30% lower relative risk (PREDIMED; Estruch et al., 2018).
• Extra-virgin olive oil is the main fat; meals center on vegetables, fruit, legumes, whole grains, nuts, and fish.
• Red and processed meat, added sugar, and refined or ultra-processed foods are kept low.
• It is a flexible pattern, not a strict diet, and adherence over time is what drives the benefit.

What the evidence shows

The landmark trial is PREDIMED, which followed about 7,447 adults in Spain at high cardiovascular risk. Participants were assigned to a Mediterranean diet supplemented with extra-virgin olive oil, a Mediterranean diet supplemented with nuts, or a low-fat control diet. Those on either Mediterranean diet had fewer major cardiovascular events (heart attack, stroke, or cardiovascular death) than the control group, around a 30% lower relative risk. This is one of the few large randomized trials of a whole dietary pattern, which is what makes it so influential.

In the interest of full transparency: the original 2013 publication was retracted in 2018 after researchers found irregularities in how some participants were randomized. The authors reanalyzed the data with appropriate methods and republished it the same year, and the main conclusion held. This guide cites the corrected 2018 version.

What the diet actually looks like

There is no single official recipe, but the pattern is consistent: extra-virgin olive oil as the primary cooking and dressing fat; plenty of vegetables, fruit, legumes (beans, lentils, chickpeas), whole grains, and nuts; fish and seafood several times a week; moderate amounts of dairy, poultry, and eggs; and only occasional red meat and sweets. Meals are largely built from whole, minimally processed foods. Traditionally the pattern includes moderate wine with meals, but alcohol carries its own health risks, so this is not a reason to start drinking.

Eat more / eat less

Frequently asked questions

Is the Mediterranean diet actually proven to work?

It has unusually strong evidence. In the randomized PREDIMED trial, people at high cardiovascular risk who followed a Mediterranean diet had roughly 30% fewer major cardiovascular events than a low-fat control group.

Do I have to drink wine or use only olive oil?

No. Extra-virgin olive oil is the traditional main fat and is well supported, but the benefit comes from the overall pattern. Wine is part of the traditional culture, not a requirement, and since alcohol carries its own risks, there is no need to start.

Why was the PREDIMED study retracted?

The 2013 version had irregularities in how some participants were randomized. The authors corrected the analysis and republished it in 2018, and the main finding of fewer cardiovascular events on the Mediterranean diet remained.

References

1. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts (Estruch et al., PREDIMED) · New England Journal of Medicine, 2018 (republished). Accessed 2026-05-26.
2. PREDIMED Study Retraction and Republication · The Nutrition Source, Harvard T.H. Chan School of Public Health. Accessed 2026-05-26.