INS and obesity due to melanocortin 4 receptor deficiency: That said, in the GLYNDIET study, a 6-month RCT consisting of 122 patients with overweight and obesity, those who followed a low-GI diet containing moderate amounts of carbohydrates had more efficacy at reducing body weight and controlling glucose and insulin metabolism compared to a high-GI diet containing moderate amounts of carbohydrates and to a low-fat and high-GI diet, in which the 3 diets were isocaloric with energy restriction (44).