Nutrition

The Mediterranean diet

Name: The Mediterranean diet
Published: 2026-10-14

Olive oil, vegetables, legumes, nuts, fish and whole grains. It is among the best-studied eating patterns for protecting the heart, easy to keep up for years, and it does not require counting calories.

Evidence BModerate Last reviewed 2026-10-14 4 min read

At a glance

What it is: a pattern, not a plan: olive oil as the main fat, plants at the centre, fish and legumes weekly, little red meat and sugar.
What the best trial found: about 30% fewer major cardiovascular events (a combined count of heart attack, stroke and cardiovascular death) in people at high risk.¹
Honest caveat: one large trial carries much of the evidence, so this guide is graded B, not A.³
Check first if you have a nut allergy or kidney disease.

What it is

The Mediterranean diet is a way of eating drawn from the traditional food of countries around the Mediterranean Sea. Its centre is plant food and olive oil. You do not need to cut calories or weigh anything: in trials the diet was not aimed at weight loss, and many people find it easy to keep up.

The Mediterranean pattern as a weekly rhythm. The top of the figure is what to build the week around.

What the research shows

The main evidence is PREDIMED, a randomised trial of 7,447 people at high cardiovascular risk who were followed for about five years. Those who ate a Mediterranean diet with extra-virgin olive oil or mixed nuts had roughly 30% fewer major cardiovascular events (heart attack, stroke, cardiovascular death) than those told to cut fat.¹ Because event rates were low, the absolute numbers are modest: this is real prevention, not a drug-sized effect.

The 2013 version of the paper was retracted and re-analysed because of problems with how some participants were randomised, then republished in 2018 with the same main conclusion.² A Cochrane review of 30 trials rates the certainty for prevention as low to moderate, with a moderate-certainty reduction in stroke.³ That is why this guide is graded B. Observational studies consistently link the pattern with lower rates of type 2 diabetes and metabolic syndrome.

How to eat it

Olive oil as your main fat. The trial used about 4 tablespoons a day; you do not need to match that, but use it in place of butter and other oils.
Vegetables and fruit at every meal.
Legumes (lentils, beans, chickpeas) at least 3 times a week.
Fish or seafood at least 3 times a week.
A handful of nuts (about 30 g) most days.
Whole grains instead of refined ones.
Red and processed meat, sweets and sugary drinks: small and rare.

Three-day example menu

	Day 1	Day 2	Day 3
Breakfast	Greek yoghurt, berries, walnuts	Wholemeal toast, tomato, olive oil, a boiled egg	Oats with apple, cinnamon and almonds
Lunch	Lentil soup, salad with olive oil, bread	Chickpea and cucumber salad with feta and herbs	Whole-wheat pasta with vegetables, olive oil, a little parmesan
Snack	An orange	A handful of almonds	Hummus with carrot sticks
Dinner	Baked salmon, roast vegetables, quinoa	Chicken with lemon and herbs, green beans, potatoes	Grilled sardines or white fish, tomato and onion salad, whole-grain bread

Shopping list for the week

Fats: extra-virgin olive oil, olives.
Plants: tomatoes, cucumbers, leafy greens, onions, garlic, peppers, courgette, aubergine, seasonal fruit, berries, lemons.
Legumes: dried or tinned lentils, chickpeas, beans.
Grains: oats, whole-wheat pasta, brown rice, wholemeal bread, quinoa.
Protein: oily fish (salmon, sardines, mackerel), white fish, chicken, eggs, Greek yoghurt, feta.
Extras: walnuts, almonds, herbs, spices.

Who should be careful

Adapt this pattern if

You have a nut allergy. Leave the nuts out and keep the olive oil and fish.
You have kidney disease. Legumes and nuts are high in potassium and phosphorus; ask for individual limits.
You take insulin or a sulfonylurea. A big change in what you eat can cause low blood sugar; tell your doctor before you start.
You take lithium or warfarin. A sudden cut in salt can raise lithium levels, and a sudden increase in leafy greens changes how warfarin works. Tell your doctor before making a large change.
You are pregnant. Choose low-mercury fish such as salmon, sardines, trout or cod, and avoid shark, swordfish and king mackerel.
You have high blood pressure. Feta, olives, cured fish and tinned legumes are salty: take small portions and rinse tinned beans.
You are trying to lose weight quickly. This pattern is not designed to beat a calorie deficit. Olive oil and nuts are energy-dense, so add them in place of other fats, not on top.

How to tell it is working

Blood pressure, cholesterol (LDL-C or ApoB), triglycerides, HbA1c or fasting glucose and waist circumference are the markers worth following, over months rather than weeks. The aim is lower long-term risk, not a quick change on the scale.

Common mistakes

Adding olive oil and nuts to an unchanged diet, which adds calories without displacing anything.
Treating it as "pasta and wine". The foundation is vegetables, legumes and fish.
Aiming for perfection. In this pattern, regular adherence matters more than precision.

How strong is the evidence

Grade B (moderate). There is a large trial and consistent observational support, but the trial's retraction and re-analysis history, the single-trial dependence and the low-to-moderate certainty in the Cochrane review keep it below A. The risks are low, and the pattern is easy to sustain, which is a point in its favour.

References

Each reference links to PubMed or the publisher. The tag shows what kind of study it is; the grade above reflects all of them together, not any single one.

Randomised trial Estruch R, et al. Primary prevention of cardiovascular disease with a Mediterranean diet supplemented with extra-virgin olive oil or nuts. N Engl J Med 2018 (PREDIMED, republished). The main trial (7,447 people at high cardiovascular risk): about 30% fewer heart attacks, strokes and cardiovascular deaths. PubMed 29897866 · DOI
Systematic review Retraction and republication: Primary prevention of cardiovascular disease with a Mediterranean diet. N Engl J Med 2018. Why the 2013 paper was withdrawn, re-analysed and republished in 2018. PubMed 29897867
Systematic review Rees K, et al. Mediterranean-style diet for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev 2019. Cochrane review: low-to-moderate certainty for prevention, which is why this guide is graded B and not A. PubMed 30864165 · DOI

How I grade the evidence

Every guide carries a grade. It describes how well the research supports the advice, not how important the advice is. Grades come from a written rubric and are re-checked as new studies appear.

AStrongConsistent results from high-quality meta-analyses or several trials, a clear size of benefit, well-understood risks.
BModerateAt least one good systematic review or several solid trials. Promising, with real uncertainty about dose, groups or the long term.
CLimited but plausibleSome human evidence, but small, mixed or specific to one condition. Reasonable and low-risk, not proven.

Grade D (animal, mechanistic or influencer-driven claims) and E (disproven or unsafe) are not published here.

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