Olive oil before carbs slows glucose rise in mice, Kyoto study finds

A Kyoto University study in mice suggests eating olive oil before carbohydrates may delay gastric emptying and blunt the early post-meal blood sugar spike, but researchers say human trials are needed.

Eating olive oil before carbohydrates may slow the rate at which the stomach empties and soften the early rise in blood sugar, according to a new study from Kyoto University published in the journal Diabetes. The research, carried out in mice, found that the fat triggered a hormonal response that appeared to alter how quickly glucose moved into the small intestine, with possible implications for how meal order affects glycaemia.

The study found that olive oil taken before glucose increased the secretion of glucagon, glucose-dependent insulinotropic polypeptide, known as GIP, and glucagon-like peptide-1, or GLP-1. Those hormones are involved in blood sugar regulation, and the researchers reported that their combined effect was linked to delayed gastric emptying and a lower early post-meal glucose spike. Similar results were seen in mouse models of type 2 diabetes and in animals with marked insulin deficiency, suggesting the mechanism may still operate even when insulin production is impaired.

The findings lend scientific support to the idea that what people eat first at a meal can matter as much as what they eat overall. Nutrition professionals have long recommended starting with vegetables, then protein, and ending with starchy foods such as rice or bread, a sequence that is thought to help flatten post-meal glucose swings. But the Kyoto work goes further by suggesting that fat itself can influence the timing of digestion through both endocrine and neural pathways.

That said, the result does not mean people should begin every meal with a spoonful of oil. Nutrition specialist Lao Gu, writing on social media, said deliberately forcing down a large dose of olive oil is unnecessary and may simply add extra calories. He argued that olive oil is better used in normal cooking, particularly with vegetables, where it can also aid the absorption of fat-soluble nutrients.

The broader message is one of moderation and practicality. The study suggests that nutrient timing may help shape blood sugar responses, but it remains an animal experiment rather than proof of a clinical strategy for people. As researchers and commentators alike noted, the next step is to test whether similar effects appear in humans and whether meal sequencing can offer a useful, sustainable tool alongside established advice on diet, weight management and diabetes care.