Dietary glycemic index and load and the risk of type 2 diabetes: Assessment of causal relations

Geoffrey Livesey, Richard Taylor, Helen F. Livesey, Anette E. Buyken, David J.A. Jenkins, Livia S.A. Augustin, John L. Sievenpiper, Alan W. Barclay, Simin Liu, Thomas M.S. Wolever, Walter C. Willett, Furio Brighenti, Jordi Salas-Salvadó, Inger Björck, Salwa W. Rizkalla, Gabriele Riccardi, Carlo La Vecchia, Antonio Ceriello, Antonia Trichopoulou, Andrea PoliArne Astrup, Cyril W.C. Kendall, Marie Ann Ha, Sara Baer-Sinnott, Jennie C. Brand-Miller

Research output: Contribution to journalReview article


While dietary factors are important modifiable risk factors for type 2 diabetes (T2D), the causal role of carbohydrate quality in nutrition remains controversial. Dietary glycemic index (GI) and glycemic load (GL) have been examined in relation to the risk of T2D in multiple prospective cohort studies. Previous meta-analyses indicate significant relations but consideration of causality has been minimal. Here, the results of our recent meta-analyses of prospective cohort studies of 4 to 26-y follow-up are interpreted in the context of the nine Bradford-Hill criteria for causality, that is: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biological Gradient, (6) Plausibility, (7) Experimental evidence, (8) Analogy, and (9) Coherence. These criteria necessitated referral to a body of literature wider than prospective cohort studies alone, especially in criteria 6 to 9. In this analysis, all nine of the Hill’s criteria were met for GI and GL indicating that we can be confident of a role for GI and GL as causal factors contributing to incident T2D. In addition, neither dietary fiber nor cereal fiber nor wholegrain were found to be reliable or effective surrogate measures of GI or GL. Finally, our cost–benefit analysis suggests food and nutrition advice favors lower GI or GL and would produce significant potential cost savings in national healthcare budgets. The high confidence in causal associations for incident T2D is sufficient to consider inclusion of GI and GL in food and nutrient-based recommendations.

Original languageEnglish
Article number1436
Issue number6
Publication statusPublished - Jun 2019


  • Alcohol
  • Causation
  • Cohort studies
  • Diabetes
  • Dietary fiber
  • Epidemiology
  • Glycemic index
  • Glycemic load
  • Meta-analysis
  • Public health

ASJC Scopus subject areas

  • Food Science
  • Nutrition and Dietetics

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    Livesey, G., Taylor, R., Livesey, H. F., Buyken, A. E., Jenkins, D. J. A., Augustin, L. S. A., Sievenpiper, J. L., Barclay, A. W., Liu, S., Wolever, T. M. S., Willett, W. C., Brighenti, F., Salas-Salvadó, J., Björck, I., Rizkalla, S. W., Riccardi, G., Vecchia, C. L., Ceriello, A., Trichopoulou, A., ... Brand-Miller, J. C. (2019). Dietary glycemic index and load and the risk of type 2 diabetes: Assessment of causal relations. Nutrients, 11(6), [1436].