When Tolerating Diet Is Not Enough: Hidden Underfeeding After Distal Gastrectomy

Background Early postoperative energy intake after gastrectomy may be insufficient and may contribute to short-term weight loss, yet whether tolerating an oral diet within a standardized clinical pathway corresponds to adequate intake remains unclear. We examined early postoperative energy intake and its association with weight loss after gastrectomy. Methods We retrospectively assessed postoperative energy intake and weight loss in patients with pStage II-III gastric cancer who underwent distal gastrectomy at our hospital between January 2012 and December 2021. Multivariable analysis using multiple regression was performed to evaluate the association between postoperative energy intake and weight loss. Results The median (interquartile range) weight loss was 2.5 (1.00-3.70) kg, corresponding to a reduction of 4.2% (1.9%-6.4%). Median energy intake was 1148 (987-1251) kcal/day, corresponding to 18.9 (15.0-21.9) kcal/kg/day based on body weight. The median oral intake rate was 81.5% (68.80-89.60) during postoperative days (PODs) 3-14 and 90.8% (78.65-98.20) during PODs 7-14. The multivariable analysis identified postoperative energy intake per body weight as a factor associated with weight loss (estimated regression coefficient = −0.18, 95% confidence interval [CI] = −0.27 to −0.09, P < .01). C-Reactive protein (CRP) level was also identified as a factor associated with weight loss (estimated regression coefficient = 0.14, 95% CI = 0.01-0.27, P = .039). Discussion Insufficient early postoperative energy intake and elevated preoperative CRP were independently associated with weight loss after distal gastrectomy. Despite apparent oral feeding success within a standardized clinical pathway, “hidden underfeeding” persisted—particularly in larger patients—warranting individualized nutritional supplementation strategies.