Background Preoperative weight loss is associated with increased complications and poorer outcomes post-major abdominal surgery. Evidence is growing for the role of Prehabilitation, preoperative nutrition counseling and preoperative ONS (oral nutritional supplements) in minimizing weight loss. ESPEN guidelines stated that Immune-modulating ONS (containing arginine, omega-3 fatty acids, and nucleotides) can be preferred and taken 5-7 days preoperatively. This retrospective study reviewed the effect of preoperative nutrition counseling and immuno-nutrition on body weight preservation and/or gain during the preoperative period.

Methods 36 patients with lower or upper GI malignancies were referred to the Dietitian before surgery. Nutritional interventions included individualized assessment, dietary counseling and an immune-modulating oral nutrition supplement (with arginine, omega-3 fatty acids, and nucleotides) 2packs daily (total 474ml) taken 5-7days before surgery for optimization of preoperative nutritional status. Pre (before intervention) and post-intervention (at day of operation) body weights, BMI, calorie and protein intakes were recorded.

Results Of the 36 patients for elective surgery, 94.4% were lower GI malignancies and 5.5% were upper GI malignancies. Patients were Underweight with BMI <18.5 (2.8%), Normal Weight BMI 18.5-22.9 (33.3%) and Overweight BMI >23 (63.9%). Mean time period between intervention to operation day was 19 (range was 6-46 days). Mean body weight gain after intervention was +0.5kg or +0.9% (t= - .17533, p=.430665). Mean increase in BMI after intervention was +0.2 (t= - 0.23796, p-value is .406302). There was a 39.4% mean improvement in calorie intake and a 51.8% improvement in protein intake after nutritional intervention.

Conclusions Pre-operative immuno-nutrition and dietary counseling significantly improved calorie and protein intakes. Body weights were successfully maintained and a 0.9% mean weight gain was observed during the preoperative time frame. Nutritional interventions should be a crucial component in preoperative prehabilitation programs for patients undergoing major abdominal surgery for malignancies. Further studies comparing historical control groups and the association between preoperative weight change on surgical length of stay (LOS), complications rates, and cost-effectiveness can be explored.