Postprandial Glycemic and Appetite Responses to Amorphophallus Konjac–Substituted Roasted Sticky Rice in Bamboo Joints (Khao Lam): A Randomized, Double-Blind, Controlled Crossover Trial in Healthy Adults

Background and objectives: Khao Lam is a traditional Thai dessert prepared from glutinous rice, sugar, coconut milk and salt and is typically roasted in bamboo joints. Unfortunately, this product contains high carbohydrates, fat and energy content, so frequent consumption may lead to more calories and sugar intake. To reduce energy and sugar content, konjac and isomaltulose were used to substitute sticky rice and sucrose in Khao Lam. However, the acute clinical effects of this reformulation Khao Lam on metabolic and appetite-related outcomes have not been investigated. Methods and study design: Accordingly, a randomized controlled trial (RCT) crossover was conducted in 45 healthy volunteers to investigate the outcomes of substituting konjac and isomaltulose in Khao Lam on postprandial glycemic responses, differences in blood glucose and hunger–satiety perception levels at 0, 30, 60, 90 and 120 minutes, incremental area under the curve (iAUC) and glycemic index (GI) prior to and following the ingestion of a standard reference (glucose solution, GLU), traditional Khao Lam (CO), Khao Lam with konjac (KS) and Khao Lam with konjac and isomaltulose (KI). Results: Blood glucose levels at 30 and 60 minutes following consumption of all Khao Lam formulas were significantly lower than those observed after GLU intake (p<0.05). Postprandial blood glucose differentiation of CO, KS and KI were significantly lower than GLU during the 0-0.5, 0-1.0 and 1-1.5 hours intervals (p<0.05). No significant differences in iAUC were observed among the Khao Lam groups; however, over the 0–2 hours period, KS exhibited the lowest iAUC compared with the other food samples. GI values for CO (GI=91), KS (GI=88), and KI (GI=88) were significantly reduced compared with GLU (p<0.05). However, all products were classified as high-GI foods. In addition, at 30 minutes post-consumption, all Khao Lam formulations elicited a significantly lower self-reported desire to eat compared with GLU (p<0.05), indicating an enhanced satiety response among participants. Conclusions: The incorporation of Amorphophalluskonjacand isomaltulosein Khao Lam provided better formulation than traditional dessert due to it being associated with improved postprandial blood glucose responses, lower GI, and enhanced satiety. However, exposure of isomaltulose to high cooking temperatures may cause caramelization, potentially increasing glycemic response; thus, its use warrants careful consideration.