Olive Oil and the Mediterranean Diet
In the traditional Mediterranean diet, olive oil is the main fat — not butter, not seed oils, not lard — and that single habit does a lot of the heavy lifting behind the diet’s good reputation. It is poured over vegetables, stirred into beans and lentils, used to cook fish, and spooned raw over just-cooked food. Around the Mediterranean it has never been a garnish or a “health food”; it is simply how you cook and how you dress a plate. The evidence we have today, taken as a whole, is encouraging about that pattern — though, as with all things food and health, it is best read with a level head rather than as a promise.
Why olive oil sits at the centre of the plate
The Mediterranean diet is not really a diet in the modern sense — it is a way of eating that grew up around the northern rim of the Mediterranean Sea, in places like southern Italy, Greece, Crete and coastal Spain. When researchers first took an interest in it in the mid-twentieth century, what stood out was not any single “superfood” but the shape of the whole: plenty of vegetables, pulses, whole grains, fruit and nuts; fish and seafood fairly often; modest amounts of dairy, eggs and poultry; red meat only now and then; and olive oil running through nearly all of it.
That last point matters more than it first appears. Because olive oil is the default fat, the diet naturally leans towards monounsaturated fat — chiefly oleic acid — rather than the saturated fat of butter and fatty meat. Extra virgin olive oil, the least processed grade, also carries polyphenols and other minor compounds from the fruit, along with vitamin E. These are the parts that give a fresh, peppery oil its bite at the back of the throat. You can read more about the grades and what separates them in our guide to olive oil grades.
It is worth being honest about one thing: olive oil is calorie-dense, like every fat, at roughly 120 calories a tablespoon. The Mediterranean pattern is not low-fat — it can be quite high in fat by percentage — but the fat comes overwhelmingly from a plant source eaten alongside vegetables and pulses, not from processed food. That context is the whole point.
What the evidence actually says
The most talked-about trial is PREDIMED, a large Spanish study whose participants were at higher-than-average cardiovascular risk. People assigned to a Mediterranean diet supplemented with extra virgin olive oil, or with nuts, had fewer major cardiovascular events over the following years than those told simply to eat a lower-fat diet. The trial was re-analysed and republished in 2018 after some enrolment issues were found, and the main conclusion held up. It is one study, in one population, and it cannot tell us everything — but alongside decades of observational work pointing the same way, it is a meaningful signal.
Beyond the headline, the broader body of research links this style of eating with better cardiovascular markers, more favourable blood lipids, and in some cohorts a lower risk of type 2 diabetes and certain other conditions. Much of the benefit almost certainly comes from the overall pattern rather than olive oil alone — you cannot cleanly separate the oil from the vegetables it is poured over. What can be said fairly is that replacing butter, margarine or fatty-meat fat with olive oil is a sensible swap that fits a well-supported way of eating.
A plain note: this is general information, not medical advice. If you have a specific condition or take medication, talk to your GP or a dietitian before making big changes.
How olive oil compares with other common fats
The figures below are approximate and rounded — real values vary by product and batch — but they show why olive oil earns its place. It is the balance of fats, plus what extra virgin oil brings beyond them, that counts.
| Fat (per 100g) | Monounsaturated | Saturated | Notable extras |
|---|---|---|---|
| Extra virgin olive oil | ~73% | ~14% | Polyphenols, vitamin E |
| Butter | ~21% | ~51% | Little to none |
| Sunflower oil | ~20-30% | ~10% | High in omega-6 |
| Coconut oil | ~6% | ~87% | Very high saturated |
Note the polyphenols line for extra virgin oil. Those compounds are one reason the least-refined grade is worth the extra money for cold uses — drizzling, dressing, finishing — where its flavour and freshness come through. For everyday cooking, ordinary olive oil is perfectly good; despite the persistent myth, olive oil is stable enough for normal home frying and sauteing. You will lose some of the delicate aromatics of a fine extra virgin oil under high heat, which is simply a reason not to waste your best bottle in the pan.
Putting it on the plate, the Mediterranean way
The practical lesson is unfussy. Use olive oil as your default fat. Cook your onions and garlic in it, roast vegetables with it, dress salads and cooked greens with it, and keep a good bottle aside to finish soups, beans and grilled fish just before serving. Pair it with the rest of the pattern — more plants, more pulses, fish over red meat — because the oil does its best work in that company, not on its own. If you are just starting out, our olive oil encyclopedia is a good place to get your bearings on styles and uses.
Common questions
Is olive oil really the healthiest fat?
It is one of the best-studied and most sensible everyday fats, largely thanks to its monounsaturated fat and, in extra virgin form, its polyphenols. “Healthiest” is a stretch for any single food — what matters is the overall diet. As a swap for butter or fatty-meat fat, olive oil is a good move.
Do I need extra virgin, or is regular olive oil fine?
Both have a similar fat profile. Extra virgin is less processed and keeps more polyphenols and flavour, so it shines in cold and finishing uses. Regular (“pure” or light) olive oil is fine for everyday cooking. Many households keep both.
Can I cook and fry with olive oil?
Yes. Olive oil is stable enough for normal home cooking, including sauteing and shallow frying. High heat dulls the delicate aromas of a fine extra virgin oil, so most cooks use an everyday grade for the pan and save the good stuff for finishing.
How much olive oil should I use?
There is no single “dose”, and it is calorie-dense at roughly 120 calories a tablespoon. Traditional Mediterranean eating uses it generously but as part of a plant-heavy plate. Let your overall diet and energy needs guide the amount rather than chasing a number.