In order to develop evidence-based recommendations and expert consensus for nutrition management of patients undergoing bariatric surgery and postoperative follow-up, we conducted a systematic literature search using PRISMA methodology plus critical appraisal following the SIGN and AGREE-II procedures . The results were discussed among all members of the GARIN group, and all members answered a Likert scale questionnaire to assess the degree of support for every recommendation . Patients undergoing bariatric surgery should be screened preoperatively for some micronutrient deficiencies and treated accordingly . A VLCD (Very Low-Calorie Diet) should be used for 4-8 weeks prior to surgery . Postoperatively, a liquid diet should be maintained for a month, followed by a semi-solid diet also for one month . Protein requirements (1-1.5 g/kg) should be estimated using adjusted weight . Systematic use of specific multivitamin supplements is encouraged . Calcium citrate and vitamin D supplements should be used at higher doses than are currently recommended . The use of proton-pump inhibitors should be individualised, and vitamin B12 and iron should be supplemented in case of deficit . All patients, especially pregnant women, teenagers, and elderly patients require a multidisciplinary approach and specialised follow-up . These recommendations and suggestions regarding nutrition management when undergoing bariatric surgery and postoperative follow-up have direct clinical applicability.