Introductionː Preoperative carbohydrate oral (CHO) drinks attenuate the surgical stress response; however, the effects of CHO supplementation on the neutrophil-to-lymphocyte ratio (NLR) as an inflammatory and immunology-based predictor remain unclear. This study evaluated the effects of preoperative CHO loading on NLR values and complications following open colorectal surgery compared with a conventional fasting protocol. Methodsː Sixty eligible participants having planned for routine and open colorectal cancer surgery from May 2020 to January 2022 were prospectively and randomly allocated to either the control (fasting) group, whose members discontinued oral intake beginning the midnight before surgery, or the intervention (CHO), group, whose members consumed a CHO solution the night before surgery and 2 h prior to anaesthesia. NLR was assessed at 06:00 h before surgery (baseline) and at 06:00 h on postoperative days 1, 3 and 5. The incidence and severity of postoperative complications were assessed by Clavien-Dindo Classification up to postoperative day 30. All data were analysed using descriptive statistics. Resultsː Postoperative NLR and delta NLR values were significantly higher in controls (p < 0.001; p < 0.001). Control group participants also demonstrated grade IV (n = 5; 16.7%, p < 0.01) and grade V (n = 1; 3.3%, p < 0.313) postoperative complications. There were no major postoperative complications in the CHO group. Discussion/Conclusion: Preoperative CHO consumption reduced postoperative NLR values and the incidence and severity of postoperative complications following open colorectal surgery, compared with a preoperative fasting protocol. Preoperative carbohydrate loading may improve recovery following colorectal cancer surgery.