# Glycemic index and glycemic load

The glycemic index (GI) ranks foods by how fast their digestible carbs raise your blood sugar, compared with pure glucose (GI = 100). A GI of 55 or under is low, 56 to 69 is moderate, and 70 or over is high. But GI ignores serving size. So glycemic load (GL) captures the real-world hit: GL = GI × available carbohydrate (g) ÷ 100. High-GI, high-GL meals cause fast glucose spikes and big insulin surges. Over time that promotes high insulin, oxidative stress, and low-grade inflammation. Those processes are tied to insulin resistance, β-cell trouble, and faster biological aging. The PURE cohort (Jenkins et al., NEJM 2021; 137,851 people across five continents) found something specific. In people with existing heart disease, the highest versus lowest GL fifth carried a hazard ratio of 1.34 (95% CI 1.08 to 1.67) for major heart events. In the prevention group (no prior disease), there was no significant GL link. A Weizmann Institute study (Zeevi et al., Cell 2015; 800 people) showed that blood-sugar responses to identical foods vary a lot from person to person. The drivers include your gut microbiome, genetics, and metabolic state. In a randomized follow-up, algorithm-based personal advice beat generic GI-based advice. The 2015 ICQC consensus backs low-GI/GL diets as evidence-based ways to prevent type 2 diabetes and coronary heart disease. It also notes that processing, ripeness, and meal makeup can shift a food's effective GI by 20 to 30 points.

## Sources

- Augustin LS, Kendall CW, Jenkins DJ, et al.. (2015). Glycemic index, glycemic load and glycemic response: An International Scientific Consensus Summit from the International Carbohydrate Quality Consortium (ICQC). Nutrition, Metabolism and Cardiovascular Diseases. https://doi.org/10.1016/j.numecd.2015.05.005
- Jenkins DJ, Dehghan M, Mente A, et al.. (2021). Glycemic Index, Glycemic Load, and Cardiovascular Disease and Mortality. New England Journal of Medicine. https://doi.org/10.1056/NEJMoa2007123
- Zeevi D, Korem T, Zmora N, et al.. (2015). Personalized Nutrition by Prediction of Glycemic Responses. Cell. https://doi.org/10.1016/j.cell.2015.11.001

---

_Canonical: https://longevity-switzerland.com/en/glossary/glycemic-index-load · Part of Longevity Cities · Updated 2026-06-22_