Glycemic Index Useless?

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The use of glycaemic index tables to predict glycaemic index of

composite breakfast meals.

Flint A, Moller BK, Raben A, Pedersen D, Tetens I, Holst JJ, Astrup A.

Department of Human Nutrition, Centre for Advanced Food Studies, The

Royal Veterinary and Agricultural University, DK-1958 Frederiksberg

C, Denmark. afl@...

Br J Nutr. 2004 Jun;91(6):979-89.

The applicability of the glycaemic index (GI) in the context of mixed

meals and diets is still debatable. The objective of the present

study was to investigate the predictability of measured GI in

composite breakfast meals when calculated from table values, and to

develop prediction equations using meal components. Furthermore, we

aimed to study the relationship between GI and insulinaemic index

(II). The study was a randomised cross-over meal test including

twenty-eight healthy young men. Thirteen breakfast meals and a

reference meal were tested. All meals contained 50 g available

carbohydrate, but differed considerably in energy and macronutrient

composition. Venous blood was sampled for 2 h and analysed for

glucose and insulin. Prediction equations were made by regression

analysis. No association was found between predicted and measured GI.

The meal content of energy and fat was inversely associated with GI (R

(2) 0.93 and 0.88, respectively; P<0.001). Carbohydrate content

(expressed as percentage of energy) was positively related to GI (R

(2) 0.80; P<0.001). Using multivariate analysis the GI of meals was

best predicted by fat and protein contents (R(2) 0.93; P<0.001).

There was no association between GI and II. In conclusion, the

present results show that the GI of mixed meals calculated by table

values does not predict the measured GI and furthermore that

carbohydrates do not play the most important role for GI in mixed

breakfast meals. Our prediction models show that the GI of mixed

meals is more strongly correlated either with fat and protein

content, or with energy content, than with carbohydrate content

alone. Furthermore, GI was not correlated with II.