Glycemic Index Values Are Surprisingly Variable, Researchers Report

The uselessness of the glycemic index, or GI, shown again.

"In work investigating the reproducibility of glycemic index values, researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University (USDA HNRCA) have reported that multiple glycemic index value determinations (measure of the rate of glucose absorption into the bloodstream) using a simple test food, white bread, resulted in a relatively high level of inter-individual (among different individuals), and intra-individual (within the same individual) variability."

In other words, you cannot trust the numbers.

No surprise.

"'Using glucose as the control food, previous studies indicate that white bread has a glycemic index of about 70,' says Lichtenstein, who is also the Gershoff professor of nutrition science and policy at the Friedman School of Nutrition Science and Policy at Tufts. 'In our study the combined average was 71, virtually identical to the published value. However, quite strikingly, individual values ranged from 44 to 132. What is critical is to determine why there is such a wide range of responses among individuals.'

In addition, within the same individual, test values varied by as much as 42 percent."

However, the one thing that is NOT "critical is to determine why there is such a wide range of responses among individuals."

That research will likely lead nowhere except to the researcher's banks.

The GI is simply dependent on too many variables.

Still, your money is being wasted.

"Lichtenstein and colleagues have received a five-year grant from the National Institute of Diabetes and Digestive and Kidney Diseases to further their understanding of the glycemic index and its utilities. The current study was supported by the U.S. Department of Agriculture's Agricultural Research Service."

It is and always will be about Calories in and Calories out.

Nothing else.

The GI is really the Garbage Index.