It’s good for your heart, could reduce dementia risk – and is certainly better for you than butter. Just three of the widely held beliefs about olive oil, and its proposed health benefits.
The condiment is, after all, a key component of the much-celebrated Mediterranean diet.
Now, fascinating research from Japan suggests another, lesser-known benefit of the popular oil; it could help prevent type 2 diabetes.
Scientists from Kyoto University found that giving a small amount to mice before they ate carbohydrates significantly reduced the dramatic spikes in blood sugar associated with the disease.
Intriguingly, this effect was said to be partly caused by increased levels of the hormone GLP-1 – the natural appetite suppressant mimicked by the blockbuster weight loss jabs.
However gram for gram, olive oil is, in fact, more calorific than butter.
‘It’s easier to eat more without realising, because people drizzle it on everything and, before you know it, you’ve consumed hundreds of extra calories,’ warns nutritionist Rob Hobson, author of The Low Appetite Cookbook.
So, what’s the truth? Is olive oil really the health elixir it’s so often painted out to be, or is it just making you fat?
New research suggests that a glug of olive oil before bread could reduce blood sugar spikes
What’s in olive oil?
The proposed benefits of olive oil are said to lie with the type of fat it is made from.
One tablespoon contains around 120 calories and 14g of fat, compared to butter at 100 calories and 11g of fat.
However while butter contains around 7g of saturated fat, there’s only 2g in the equivalent amount of olive oil.
Saturated fat is the type that adults must limit to between 20 and 30g per day, as too much can damage the blood vessels and raise the risk of heart disease.
‘The main fat in olive oil is oleic acid, which is what’s known as a monounsaturated fat,’ explains Mr Hobson, who, in 2022 was awarded health writer of the year by The Health Food Manufacturers’ Association (HFMA).
‘It also contains smaller amounts of a type called polyunsaturated fats, mainly linoleic acid, which is an omega-6 fat.
‘Both monounsaturated and polyunsaturated fats are beneficial for heart health, particularly when they replace saturated fats.’
These ‘healthy’ fats are useful for removing LDL or ‘bad’ cholesterol from the blood vessels, reducing heart risk.
‘The omega-6 fat in olive oil is also an essential fatty acid that our bodies need but can’t make themselves.’
Olive oil also contains naturally occurring plant compounds called polyphenols, which have antioxidant properties. These microscopic substances help protect cells from damage.
A 2022 meta-analysis of 36 studies published in the Journal of Clinical Nutrition found that 25g per day of olive-oil (nearly two tablespoons) was associated with lower risks of cardiovascular disease, type 2 diabetes and all-cause mortality.
However scientists say the findings should be taken with a pinch of salt as the data is observational – meaning there could be other reasons why study participants had better health outcomes.
Meanwhile Mr Hobson says there’s a critical mistake that many people make when jumping on the ‘healthy fat’ bandwagon.
Award-winning nutritionist Rob Hobson says olive oil does contain heart healthy compounds but can result in a calorie surplus
‘People think that adding olive oil to the diet will result in a benefit. In fact, it’s about swapping fats you already use, like butter and margarine, for olive oil,’ he says.
Mr Hobson adds that this particularly applies to those attempting to lose weight.
‘Just because something is good for us doesn’t mean we need unlimited amounts of it,’ he said.
‘Unlike foods such as nuts or avocados, oil doesn’t come packaged with fibre or much else that would fill us up and stop us snacking, adding excess calories.’
Quantity is key. Many recipes suggest two to four tablespoons of olive oil for a tray of roasted vegetables, taking the calorie count up by up to 480 calories.
Mr Hobson suggests attempting to stay between one and two tablespoons. ‘Use a spoon to measure rather than pouring straight from the bottle,’ he adds.
Is extra-virgin better?
Not all olive oils contain the same amount of polyphenols. This depends on things like the variety of olive, when it’s harvested and also how the oil is produced and stored.
‘Extra-virgin olive oil will contain more of the vitamins and potentially health-promoting compounds than olive oil, as it is the first extraction of the oil from the olives,’ explains Professor Duane Mellor, a registered dietitian and researcher at Aston University.
In 2018, Spanish researchers assigned 7,447 heart patients to one of three diets: a Mediterranean diet supplemented with extra-virgin olive oil; a Mediterranean diet supplemented with mixed nuts; or a reduced fat control diet.
After five years, those following either of the Mediterranean diets had fewer major cardiovascular events, such as heart attacks and strokes, than those in the control group.
In 2026 scientists re-analysed the data and found higher extra virgin olive oil consumption was associated with lower cardiovascular risk, while ordinary olive oil showed weaker associations.
What about other ‘healthy’ oils?
Rapeseeed oil – a vegetable oil extracted from the seeds of the rapeseed plant – has similar health properties to olive oil, experts say.
‘Rapeseed oil is also rich in monounsaturated fats, contains omega-3 fats and has around half the saturated fat of olive oil,’ says Mr Hobson, who adds that there’s no difference in calorie count.
The quantity of monounsaturated fats and heart-boosting polyphenols is lower in rapeseed oil, compared to olive.
Sesame oil has around the same saturated fat as olive oil, but is also rich in healthy monounsaturated fats, as well as unique antioxidant compounds called sesamin and sesamol.
Coconut oil, however, is best eaten sparingly, Hobson says, as a tablespoon contains a huge 14g of saturated fat – more than half of a woman’s recommended daily intake.
‘If cooking at high temperatures, rapeseed oil or sesame oil is probably better, because you’ll get less smoke,’ adds Prof Mellor.
