Objective To investigate the effects of konjac glucomannan (KGM) on glycemic indicators and insulin resistance in obese individuals with prediabetes.

Methods A total of 102 obese individuals diagnosed with prediabetes at the outpatient department of West China Hospital, Sichuan University, between July 2021 and June 2022 were recruited and randomly assigned to either the experimental group (KGM group) or the control group for a three-month trial. All subjects followed personalized dietary and exercise regimens, with the KGM group additionally consuming 60 g of konjac-based dietary fiber biscuits daily to partially replace carbohydrates. This study aimed to examine the impact of KGM on fasting blood glucose, and to explore changes in 2-hour postprandial glucose, insulin-related indicators, and obesity-related parameters in the two groups of subjects.

Results A total of 41 participants in the KGM group completed the trial, with a compliance rate of 77.36%. The control group had 38 completers, with a compliance rate of 77.55%. After three months of dietary and exercise intervention, the effective rate of fasting blood glucose control was 100% in the KGM group, significantly higher than the 82% observed in the control group. The KGM group also had higher effective rates in reducing fasting blood glucose, fasting insulin, insulin resistance, insulin sensitivity, body mass, and waist circumference compared to the control group (P < 0.05). However, there were no statistically significant differences between the two groups in body mass index, 2-hour postprandial blood glucose, 2-hour postprandial insulin, or effective control of pancreatic β-cell activity (P > 0.05). During the trial, two participants in the KGM group experienced severe abdominal discomfort, which resolved after discontinuing the biscuits; two cases reported transient diarrhea, and one case reported increased anal flatulence.

Conclusion KGM can effectively control fasting blood sugar and promotes weight loss, lowers blood sugar, and enhances insulin sensitivity in obese individuals with prediabetes.