Background: Preoperative carbohydrate (CHO) loading improves patient outcomes but is not extensively studied in individuals with diabetes mellitus (DM), resulting in limited professional recommendations. This study examined postprandial glycemic responses and gastric emptying rates following consumption of a CHO drink in adults with and without DM.Methods: A single-arm, nonrandomized pilot trial was conducted in adults without DM (non-DM) (47.5 ± 2.5 years), with pre-DM (55.8 ± 3.0 years), and with type 2 DM (56.2 ± 2.5 years). Following an overnight fast, participants consumed a 50 g CHO drink followed by 1.5 g liquid paracetamol. Venous blood samples were collected at baseline (ie, t = 0 min) and 15,30, 45, 60, 90, 120, 150, 180, 210, and 240 min for plasma glucose and serum insulin and paracetamol concentrations to assess gastric emptying.Results: Participants with DM were older and had a higher body mass index than non-DM participants (31.2 ± 0.9 vs 28.2 ± 0.9). Fasting glucose and hemoglobin A1c levels differed significantly across groups (non-DM: 95.4 ± 3.6 mg/dl and 5.2% ± 0.1%; pre-DM: 111.6 ± 3.6 mg/dl and 5.8% ± 0.1%; DM: 167.4 ± 3.6 mg/dl and 7.2% ± 0.1%). Compared with the non-DM group, DM had increased glucose responses at 30-180 min. Glucose returned to baseline at 150 min in the non-DM and pre-DM groups compared with 210 min in the DM group. Paracetamol concentrations were not significantly different between the non-DM and DM groups.Conclusion: Blood glucose returned to baseline within ~2.5 h in non-DM and pre-DM groups and ~3.5 h in participants with DM following ingestion of a CHO drink. No consistent differences in gastric emptying rates were observed between participants with and without DM.