The Effect of Intensive Dietary Education on Nutritional Status After Gastrectomy(SING)

Inclusion Criteria: * histologically proven primary gastric adenocarcinoma, * T1N0, T1N1, T2N0, which are assessed by computed tomography (CT) scan (AJCC 8th classification) and intraoperative surgical staging * location of primary tumor; antrum, or angle, , lower body or mid body of the stomach * No evidence of other distant metastasis, * age ≥ 20 year old, ≤ 75 year old * no prior or posterior treatment of chemotherapy or radiation therapy against any other malignancies * adequate organ functions defined as indicated below: 1. WBC count: 3000/mm3 \~12,000/mm3, 2. \> serum Hemoglobin 8.0 g/dL 3. \> serum Platelet 100 000/mm3, 4. \< serum AST 100 IU/L, 5. \<serum ALT 100 IU/L, 6. \< Total Bilirubin 2.0 mg/dL, * written signed informed consent Exclusion Criteria: * active double cancer (synchronous double cancer and metachronous double cancer within five disease-free years), excluding carcinoma in situ (lesions equal to intraepithelial or intramucosal cancer), * gastric remnant cancer * ≥T3, T4 in surgical staging before resection * N2 or more (number of metastatic lymph nodes ≥3) in CT scan * histologically rare variants in World Health Organization (WHO) Classification such as Adenosquamous, Hepatoid, Squamous cell, Undifferentiated, neuroendocrine carcinoma and others * pregnant or breast-feeding women, * mental disorder(diagnosed with mental disorder on medical record), * unstable angina or myocardial infarction within 6 months of the trial, * unstable hypertension, * diabetes mellitus on insulin, * severe respiratory disease requiring continuous oxygen therapy, * previous upper abdominal surgery except laparoscopic cholecystectomy, * surgical complication