Purpose Increasing secretion and production of glucagon-like peptide-1 (GLP-1) by continuous ingestion of certain food components has been expected to prevent glucose intolerance and obesity. In this study, we examined whether a physiological dose (5% weight in diet) of digestion-resistant maltodextrin (RMD) has a GLP-1-promoting effect in rats fed a high-fat and high-sucrose (HFS) diet. Methods Rats were fed a control diet or the HFS (30% fat, 40% sucrose wt/wt) diet supplemented with 5% RMD or fructooligosaccharides (FOS) for 8 weeks or for 8 days in separated experiments. Glucose tolerance, energy intake, plasma and tissue GLP-1 concentrations, and cecal short-chain fatty acids concentrations were assessed.Results After 4 weeks of feeding, HFS-fed rats had significantly higher glycemic response to oral glucose than control rats, but rats fed HFS + RMD/FOS did not (approx. 50% reduction vs HFS rats). HFS + RMD/FOS-fed rats had higher GLP-1 responses (similar to twofold) to oral glucose, than control rats. After 8 weeks, visceral adipose tissue weight was significantly higher in HFS-fed rats than control rats, while HFS + RMD/FOS rats had a trend of reduced gain (similar to 50%) of the tissue weight. GLP-1 contents and luminal propionate concentrations in the large intestine increased (> twofold) by adding RMD/FOS to HFS. Eight days feeding of RMD/FOS-supplemented diets reduced energy intake (similar to 10%) and enhanced cecal GLP-1 production (similar to twofold), compared to HFS diet.Conclusions The physiological dose of a prebiotic fiber promptly (within 8 days) promotes GLP-1 production in rats fed an obesogenic diet, which would help to prevent excess energy intake and fat accumulation.