Does food insulin index in the context of mixed meals affect postprandial metabolic responses and appetite in obese adolescents with insulin resistance? A randomised cross-over trial.

The food insulin index (II) is a novel classification to rank foods based on their physiological insulin demand relative to an isoenergetic reference food and may be a valid predictor of postprandial insulin responses and appetite. The present study aimed to compare the postprandial metabolic responses and appetite sensations to two macronutrient- and glycaemic index-matched meals with either high or low II in obese adolescents with insulin resistance (IR). A randomised, single-blind and cross-over trial included fifteen obese adolescents aged 12-18 years with IR. All participants were provided with two different breakfasts: low glycaemic index, low insulin index (LGI-LII) and low glycaemic index, high insulin index (LGI-HII), with a 1-week washout period between meals. At time 0 (just before breakfast), 15, 30, 45, 60, 90, 120, 180 and 240 min after the meal, serum glucose, insulin and C-peptide levels and appetite scores were measured. At the end of 4 h, participants were served ad libitum lunch. Early (0-30 min), late (45-240 min) and total (0-240 min) postprandial insulin responses were lowered by 56·1, 34·6 and 35·6 % after the LGI-LII meal v. LGI-HII meal (P < 0·05). The feeling of hunger was also decreased by 25·8 and 27·5 % after the LGI-LII meal v. LGI-HII meal during the late and total responses (P < 0·05). The calculation II of meals or diets may be a useful dietary approach to reduce postprandial hyperinsulinaemia and the perceived hunger in obese adolescents with IR.