What exactly is a Mediterranean diet

The Mediterranean diet is a pattern, not a prescription. It emphasizes plant foods, olive oil, and fish while limiting meat and dairy.

The evidence defines it fairly consistently. In a 2013 study of 929 adults in Palermo, the Mediterranean pattern was characterized by high intakes of fruit, milk and cheese, olive oil, vegetables, pasta, and bread [1]. A separate review comparing healthy diets worldwide reported that the Mediterranean pattern provides about 43% of calories from carbohydrates, 13% from protein, and 42% from fat, with 9% from saturated fat [2]. That is a moderately high-fat diet, with most of the fat coming from olive oil and fish rather than animal sources.

The largest trial testing this pattern is the PREDIMED study, which randomized 7,447 high-risk adults to a Mediterranean diet with extra-virgin olive oil, one with nuts, or a low-fat control [3]. Over a median of 4.8 years, the combined Mediterranean groups showed a 30% relative risk reduction in the composite endpoint of heart attack, stroke, or cardiovascular death [3]. That is a real clinical outcome, not a surrogate.

But the evidence has limits. The PREDIMED trial was stopped early, and the control group received only advice to reduce fat, not a structured diet [3]. The meta-analysis of intervention trials shows the Mediterranean pattern lowers C-reactive protein by about 1 mg/L and interleukin-6 by about 0.4 pg/mL [4], but those are modest changes. The pattern is also not a single thing: studies use different scoring systems, and what counts as "Mediterranean" in Spain differs from what it means in Greece or Italy.

My call: the Mediterranean diet is a well-defined plant-forward, high-fat pattern with moderate-quality trial evidence for reducing cardiovascular events in high-risk adults. Confidence: moderate.