Olive oil is the face of Mediterranean eating, so it is easy to assume that more is always better. It is a fat, though, and fat is the most calorie-dense thing on your plate. This guide shows what a spoonful actually adds up to, what the research says about "more olive oil", and how to fit it into an ordinary day.
A level tablespoon (15 ml) weighs about 13.5 g. It holds roughly 120 kcal and about 13.5 g of fat, with no carbohydrate or protein. Around three quarters of that fat is monounsaturated; only about 14% is saturated, which is far less than butter (about 50%). One teaspoon is a third of that: roughly 40 kcal.
So a "generous glug" of three tablespoons is already around 360 kcal, about as much as a bowl of porridge with fruit. Nothing wrong with that, as long as you know it is there.
Two big pieces of evidence are usually quoted, and both are worth reading with their limits in mind.
In a Harvard analysis of about 92,000 US health professionals followed for 28 years, people who used more than 7 g of olive oil a day (about half a tablespoon) had around 19% lower risk of dying from cardiovascular disease than people who rarely or never used it. Swapping 10 g a day of butter, margarine, mayonnaise or dairy fat for olive oil was linked to lower mortality too. This was an observational study: it shows a link, not proof, and the group was mostly white health professionals.
The PREDIMED trial in Spain gave around 7,400 adults at high heart risk a Mediterranean diet with free extra virgin olive oil, a Mediterranean diet with nuts, or low-fat advice. The olive oil group had about 31% lower risk of major cardiovascular events (heart attack, stroke or cardiovascular death), a hazard ratio of 0.69. Note that the authors had to withdraw and republish the 2013 paper in 2018 because of randomisation problems at some sites, and the new estimates held up but come with that caveat. The oil was also part of a whole way of eating, not a stand-alone fix.
The honest summary: olive oil in place of butter and other saturated fats looks good for your heart; there is no proven "magic amount".
Extra virgin oil keeps more of the natural plant compounds called polyphenols. The European Union allows a claim that olive oil polyphenols "contribute to the protection of blood lipids from oxidative stress", but only for oil that contains at least 5 mg of hydroxytyrosol and related compounds per 20 g. Most labels do not state this, so a good rule is to use extra virgin when the flavour matters (dressings, drizzling) and not to worry about it for every pan.
Use it where it replaces something else: oil on vegetables instead of butter, a dressing instead of a creamy sauce, beans and fish cooked in oil. Measure with a spoon for a week so that a "drizzle" does not quietly turn into four tablespoons. Pair it with plants and wholegrains rather than adding it to an already rich meal.
NHS guidance advises most adults to keep saturated fat under about 30 g a day for men and 20 g for women, and to swap it for unsaturated fats where possible.
This is general information, not medical advice. If you have a medical condition, are pregnant or breastfeeding, have or have had an eating disorder, or take medication (especially for diabetes, blood pressure or cholesterol), talk to your doctor or a registered dietitian before changing how you eat. Olive oil is not a treatment for any condition.