Most of us reach for olive oil without a second thought.
It is the golden darling of the Mediterranean diet, friendlier to the heart than butter, and jolly good on a salad.
Now there is a curious new wrinkle worth knowing about.
The ‘healthy’ fat with a hidden catch. Image Source: Pixabay / Pexels
The ‘fat first’ findings
Researchers at Kyoto University have been studying the order in which we eat.
Giving mice olive oil before rather than after glucose reduced an early rise in blood glucose levels. It also slowed gastric emptying. In one test, mice were given olive oil 15 minutes before receiving glucose.
The timing mattered. Mice fed olive oil first had significantly lower blood glucose immediately after the meal.
Marked reductions appeared at the 15 and 30 minute marks, although the effects seemed to diminish by 60 minutes.
A possible explanation involves a hormone that has attracted plenty of attention. Eating certain foods before carbs may trigger the secretion of glucagon-like peptide-1 (GLP-1).
That is the appetite-suppressing, insulin-boosting hormone mimicked by drugs like Ozempic. Encouragingly, these positive outcomes persisted even in mice with type 2 diabetes and severe insulin deficiency.
Before you rearrange your dinner, note the obvious. The experiments were conducted in mice; the study was published in the journal Diabetes in 2026.
What works in a laboratory mouse does not always translate to humans. Treat this as promising rather than proven. As always, speak with your GP before changing anything, particularly if you manage diabetes.
Still, lead author Daisuke Yabe offered a tidy summary. He says the order in which nutrients reach the gut can engage a coordinated hormone-nerve response.
That response changes how quickly the stomach delivers glucose to the intestine.
Olive oil offers heart-health benefits, but experts say excessive use can quickly add hidden calories to a diet. Image Source: PandaStudio / Shutterstock
Researchers also tested other fats; olive oil generally performed the best. Flaxseed oil and lard produced similar results in some measures.
Here is where good intentions trip people up. Olive oil is not a free pass. One tablespoon carries about 120 calories and 14g of fat, slightly more than butter. Its advantage is the fat type; only around 2g is saturated, compared with roughly 7g in butter.
The real benefit comes from replacing butter and margarine with olive oil, not drizzling extra on everything. Nutritionist Rob Hobson suggests sticking to one or two tablespoons. He advises measuring with a spoon rather than pouring from the bottle.
It may well be. A 2026 re-analysis of the landmark PREDIMED trial, involving participants aged 55 to 80, examined long-term olive oil intake.
High cumulative extra-virgin olive oil intake reduced major cardiovascular disease risk. Common olive oil showed weaker associations by comparison.
How does olive oil stack up against other oils?
For variety in the kitchen, consider canola oil, also called rapeseed oil. It provides plenty of monounsaturated fats and some omega-3s, with roughly half the saturated fat found in olive oil.
Experts say measuring olive oil rather than pouring freely can help manage portions. Image Source: rawpixel.com / Magnific
It does, however, contain fewer polyphenols and other potentially beneficial plant compounds.
Sesame oil is another option, offering antioxidants such as sesamin and sesamol. Its saturated fat content is comparable to olive oil’s.
Coconut oil is much higher in saturated fat, so it is best kept for occasional use in small amounts.
For cooking at higher temperatures, refined canola or sesame oil may be suitable choices. Heat tolerance varies with the type of oil and how it has been processed.
Olive oil can absolutely be part of a healthy diet, especially when it replaces less healthy fats like butter or margarine. But it’s not a magic bullet, and it’s easy to overdo it.
Stick to one or two tablespoons per meal, choose extra-virgin when you can, and remember that even the healthiest oil is still, well, oil.
Key takeaways
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A Kyoto University study found that giving mice olive oil before carbohydrates blunted early blood sugar spikes, but this has not yet been confirmed in humans.
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The effect involved GLP-1, the same hormone mimicked by weight loss drugs like Ozempic, and persisted in diabetic mice.
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Olive oil works best as a swap for butter or margarine, not an extra; one to two tablespoons a day is plenty.
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A 2026 re-analysis of the PREDIMED trial linked extra-virgin olive oil to greater heart benefits than ordinary olive oil in older adults.
Do you use olive oil in your cooking? Have you noticed any health benefits, or pitfalls? Do you prefer another oil, or are you still loyal to butter? Share your thoughts and tips in the comments below.
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