Glycemic index predicts blood sugar level after meal

NEW YORK (Reuters Health) - Assessing a meal using the glycemic index, which lists the quality of carbohydrates contained in many common foods, appears to be a good way to predict the effect a meal will have on blood sugar levels, important information for diabetes, according to the results of a study published in the American Journal of Clinical Nutrition.

Dr. Thomas M. S. Wolever, of the University of Toronto and colleagues examined whether overall carbohydrate content and glycemic index of individual foods, as given in published tables, determined the effects of a realistic mixed meal on the blood sugar in normal subjects.

The team measured the responses to six test meals in 16 subjects in Sydney and eight meals in 10 subjects in Toronto, and then pooled the results. The meals varied in amount of calories, protein, fat, available carbohydrates and glycemic index score.

The blood sugar and insulin responses to the Sydney test meals varied over a 3-fold range. For the Toronto test meals, the blood sugar responses varied over a 2.4-fold range.

The team found no correlation between the blood sugar levels and fat or protein content of the test meal, but there was a significant correlation with carbohydrate content and glycemic index alone, which accounted for 88 percent of the variation in the blood sugar response.

"The good news is that the glycemic index works," Wolever said in a press release. "For sensible people it makes a lot of sense" It uses a "simple proportional measure -- like mixing paint."

SOURCE: American Journal of Clinical Nutrition, June 2006.