Should obese patients be counselled to follow a low‐glycaemic index diet? No

Summary In diabetes research the glycaemic index (GI) of carbohydrates has long been recognized and a low GI is recommended. The same is now often the case in lipid research. Recently, a new debate has arisen around whether a low‐GI diet should also be advocated for appetite‐ and long‐term body weight control. A systematic review was performed of published human intervention studies comparing the effects of high‐ and low‐GI foods or diets on appetite, food intake, energy expenditure and body weight. In a total of 31 short‐term studies (<1 d), low‐GI foods were associated with greater satiety or reduced hunger in 15 studies, whereas reduced satiety or no differences were seen in 16 other studies. Low‐GI foods reduced ad libitum food intake in seven studies, but not in eight other studies. In 20 longer‐term studies (<6 months), a weight loss on a low‐GI diet was seen in four and on a high‐GI diet in two, with no difference recorded in 14. The average weight loss was 1.5 kg on a low‐GI diet and 1.6 kg on a high‐GI diet. To conclude, there is no evidence at present that low‐GI foods are superior to high‐GI foods in regard to long‐term body weight control. However, the ideal long‐term study where ad libitum intake and fluctuations in body weight are permitted, and the diets are similar in all aspects except GI, has not yet been performed.