Glycaemic indexGI

The glycaemic index (GI) ranks carbohydrate foods by how much and how quickly they raise blood glucose compared with a reference. High-GI foods spike blood sugar faster; low-GI foods release it more gradually.

It matters as a rough guide to blood-sugar response, but it has real limits: GI is measured for foods eaten alone, whereas mixed meals with protein, fat and fibre behave very differently, and individual responses vary. It's a starting point, not a rule.

In practice, overall diet quality, total carbohydrate and how foods are combined matter more than GI alone; continuous glucose monitoring shows just how personal these responses can be.