TempoLife › Nutrition & fitness glossary › Glycemic index
Glycemic index
A 0–100 scale of how fast a carbohydrate food raises blood sugar versus pure glucose.
The glycemic index (GI) ranks carbohydrate foods from 0 to 100 by how quickly and how much they raise blood sugar, compared with pure glucose at 100. High-GI foods (like white bread or sugary drinks) spike blood sugar fast; low-GI foods (like lentils, most vegetables, oats) release it more slowly.
GI is useful context but an imperfect guide on its own. It is measured on a fixed carbohydrate amount eaten alone, whereas real meals mix protein, fat and fibre that all blunt the response. Glycemic load — GI adjusted for the actual portion — is often a more realistic picture than GI alone.
For most people the practical takeaways are simple: pairing carbohydrates with protein, fat or fibre softens the blood-sugar rise, and whole, less-processed foods tend to sit lower on the scale. GI matters more for people managing diabetes; for general eating, total intake and food quality matter more than chasing a low number.
Frequently asked questions
Glycemic index?
A 0–100 scale of how fast a carbohydrate food raises blood sugar versus pure glucose. The glycemic index (GI) ranks carbohydrate foods from 0 to 100 by how quickly and how much they raise blood sugar, compared with pure glucose at 100. High-GI foods (like white bread or sugary drinks) spike blood sugar fast; low-GI foods (like lentils, most vegetables, oats) release it more slowly.
