Dietary carbohydrates result in different postprandial blood glucose and insulin responses, depending on the rate of digestion. The glycaemic index (GI) classification allows for ranking foods according to their effect on the glycaemic response: a high glucose response (high GI) or low glucose response (low GI). There has been great interest in recent years in whether low-GI foods are more satiating and lead to lower body weight than high-GI foods when incorporated into whole diets. Only a few studies with similar macronutrient and fibre intake have assessed the effect of GI on body weight. These studies, ranging from 5 to 16 weeks, have not been able to show improved satiation or lower energy intake or body weight. However, in one study the interesting observation was made that total fat mass was decreased. Further long-term studies using adequate differences in GI are needed to determine whether low-GI diets can beneficially affect long-term body weight homoeost asis in humans. Keywords: energy intake; fat mass; glucose; glycaemic index; insulin; obesity