Introduction/Objective The ideal reconstruction procedure after total gastrectomy should replace all lost functions of the stomach. The aim of this study was to evaluate the usefulness of preserving the duodenal passage in subsequent improvement of body weight (BW) and body mass index (BMI) in patients with gastric cancer after total gastrectomy. Methods A total of 30 patients with gastric cancer were prospectively randomly divided into a group of reconstruction with double-tract (n = 15) and a group of reconstruction with simple Roux-en-Y after total gastrectomy. They were stratified by sex, age, their anthropometric measurements (BW, BMI), primary tumor localization, Lauren's classification, TNM stage classification, length of hospital stay, operation duration, postoperative complications, and mortality. Postoperatively, BW and BMI were measured at three, six, and 12 months and compared between the two groups. Results The clinical group of double-tract patients had significantly higher the values of BW in the postoperative period after six (66.6 ± 4.9 vs. 61.7 ± 7.6; p < 0.05 paired Student's t-test) and after 12 months (67.0 ± 4.9 vs. 62.3 ± 7.2; p < 0.05 paired Student's t-test) compared to the group of Roux-en-Y patients. On the other hand, the clinical group of double-tract patients also had significantly higher the values of BMI in postoperative period after 12 months (23.6 ± 1.1 vs. 22.5 ± 1.6; p < 0.05 paired Student's t-test) in relation to the Roux-en-Y group of patients. Conclusion Reconstruction procedure carried out after total gastrectomy which implies preserving the duodenal passage has significant increase of BW and BMI, compared to reconstruction procedure without the preservation of the duodenal passage.