Eating olive oil before carbs has a surprising effect on blood sugar
A simple change in the order you eat your food could help prevent blood sugar spikes. Scientists discovered that giving mice olive oil before carbohydrates slowed digestion and activated a surprising combination of hormones and nerve signals that helped regulate blood sugar, even in mice with type 2 diabetes.
Key points
- Research in mice found that eating olive oil before glucose reduced the initial rise in blood sugar compared with taking the oil afterward.
- The effect persisted in mice with type 2 diabetes and severe insulin deficiency, and was reduced only when both glucagon and GLP-1 signaling were blocked at once.
- The experiments were conducted in mice, and the researchers say clinical studies are needed to confirm whether the same mechanisms apply in humans.
New research in mice suggests that the order in which foods are eaten can affect blood sugar levels. Consuming fat before carbohydrates reduced the sharp rise in blood sugar that usually follows a meal, according to the study.
The work was led by an international research team and involved experiments at Kyoto University. Corresponding author Daisuke Yabe said the group has long been interested in practical dietary approaches that people can continue in everyday life.
How the experiments were run
After an overnight fast, mice were divided into three groups. One received water followed by glucose, a second received olive oil followed 15 minutes later by glucose, and a third received glucose first with olive oil given 15 minutes afterward.
The scientists measured blood glucose and several hormones involved in blood sugar regulation, including insulin, glucagon, GIP and GLP-1. They also gave the mice acetaminophen to estimate how quickly the stomach emptied. Further experiments used mice with type 2 diabetes, mice lacking the GLP-1 receptor, and mice whose vagus nerves were surgically interrupted below the diaphragm.
Our findings suggest that the order in which nutrients reach the gut can engage a coordinated hormone-nerve response that changes how quickly the stomach delivers glucose to the intestine
— Daisuke Yabe
What the results showed
When olive oil was given before glucose, the initial rise in blood sugar was smaller than when the oil came afterward. The earlier fat intake also slowed gastric emptying and stimulated an early increase in glucagon, GIP and GLP-1.
Blocking glucagon signaling alone or GLP-1 signaling alone did not remove the benefit, but blocking both at the same time reduced it. The vagus nerve experiments indicated that nerve communication also contributes to the response. The effects were also seen in mice with type 2 diabetes and severe insulin deficiency.
Implications and next steps
The findings offer a biological explanation for why eating fat before carbohydrates may limit blood sugar spikes, involving digestive hormones, pancreatic signals and the nervous system working together. Adjusting meal order is simple and may be easier to maintain than diets that avoid whole food groups.
However, the experiments were conducted in mice, and the same effects have not yet been established in humans through this research. The researchers say additional clinical studies are needed to determine whether the mechanisms can improve blood sugar regulation in people with or without diabetes.
