Dietary glycemic index and glycemic load in relation to general obesity and central adiposity among adults

Although the association between dietary Glycemic Index (GI), Glycemic Load (GL) and general/abdominal obesity has extensively been examined, limited data are available in this regard in developing countries. The aim of this study was to examine the association between dietary GI and GL with general and abdominal obesity.

This cross-sectional study was conducted among adults in Isfahan, Iran. Dietary GI and GL were assessed using a validated dish-based 106-item semi-quantitative food frequency questionnaire (DS-FFQ). Data regarding height, weight and waist circumference were collected using a self-reported questionnaire. Overweight or obesity was defined as body mass index ≥25 kg/m², and abdominal obesity was defined as waist circumference ≥80 cm for women and ≥94 cm for men.

There was no significant association between dietary GI and GL and general obesity. After adjustment for potential confounders, participants in the highest quintile of dietary GI had a higher chance for abdominal obesity (OR: 1.29; 95% CI: 1.01-1.64), compared with those in the lowest quintile. No significant association was observed between dietary GL and abdominal obesity. After adjustment for potential confounders, women in the top quintile of dietary GI had higher chance for abdominal obesity compared with those in the bottom quintile (OR: 1.48, 95% CI: 1.02-2.15). No significant association was found between dietary GI and abdominal obesity among men. We failed to find any significant association between dietary GI and general obesity in either gender [Comparing top vs. bottom quintiles, for men: OR: 0.97; 95% CI: 0.74-1.29 and for women: OR: 1.01; 95% CI: 0.75-1.40]. No significant association was found between dietary GL and general [for men: OR: 1.13; 95% CI: 0.85-1.49 and for women: OR: 1.01; 95% CI: 0.76-1.35], as well as abdominal obesity [for men: OR: 1.21; 95% CI: 0.88-1.67 and for women: OR: 1.25; 95% CI: 0.88-1.77].

We found a significant positive association between dietary GI and abdominal obesity. When we conducted analyses stratified by gender, we also observed such association in women, but not in men. No other significant associations were observed between dietary GI and GL with general or abdominal obesity.