94 Background: Postoperative weight loss could have a negative effect on quality of life and prognosis of gastric cancer patients. We have already shown that daily nutritional intervention with an oral elemental diet (ED) attenuated the short-term postoperative percentage of body weight loss (% BWL) in post-gastrectomy patients, especially in underwent total gastrectomy (TG). This study was conducted to evaluate the postoperative long-term BWL of nutritional intervention. Methods: This study was conducted in a cohort of consecutive patients which were randomly allocated to receive the control or ED diet in the original trial. Control group received the regular diet alone after gastrectomy, while ED group received 300 kcal of ED plus their regular diet for 6–8 weeks. The primary endpoint was the % BWL from the presurgical bodyweight to that at 1 year after surgery by surgical type. Secondary endpoints were changes in nutrition-related blood parameters. Results: One hundred six of registered patients in the original trial were eligible for efficacy analyses. There was not significant difference in the % BWL between the two groups (9.13 ± 7.72 % vs. 7.09 ± 7.49 %, respectively; p = 0.171). The % BWL at one year after surgery was significantly lower in ED group than in control group among patients who underwent TG (n = 19 and 17, respectively; 9.66 ± 5.98% vs. 15.11 ± 6.78%, respectively; p = 0.015), but not in patients who underwent distal gastrectomy (DG) (n = 38 and 32, respectively; 5.81 ± 7.91% vs. 5.96 ± 6.20%, respectively; p = 0.933). A multivariate analysis revealed that only type of gastrectomy was independently associated with % BWL at 1 year after surgery. And in total gastrectomy, ED administration was independently associated with % BWL. Total lymphocyte count in ED group increased more than that in control group at 1 year after surgery. Conclusions: Nutritional intervention with ED at 300 kcal per day for 6–8 weeks reduced body weight loss at 1 year as well as 6-8 weeks after surgery in patients who underwent total gastrectomy. Clinical trial information: 000023455.