Introduction: The aims of this study were to determine the proportion of patients who meet international recommendations for bariatric surgery and to assess the association between weight loss and dropout rate during diet therapy. Material and Methods: Retrospective cohort study performed using data from clinical records of patients who underwent sleeve gastrectomy in a private clinic of Lima, Peru. Two outcomes were evaluated, eligibility for bariatric surgery according to international recommendations (BMI≥40kg/m2 or ≥35kg/m2 with comorbidities) and abandonment before and after starting nutritional management (no nutritional assessment after 60 days from the previous visit without achieving ideal BMI). The exposure was the percentage of weight lost in the first five weeks after surgery split into <10% and ≥10%. Poisson regression was used and relative risks and 95% confidence intervals (95%CI) were calculated. Results: Data from 423 medical records of bariatric patients, mean age 39.2 years (±12.3), 294 (69.5%) women, were analyzed. Only 117 (27.7%) patients met international recommendations for bariatric surgery. Before starting nutritional management, 48/117 (41%) abandoned treatment, whereas an additional 29/69 (42.0%) abandoned before six months of nutritional management. Patient losing ≥10% of weight in the first month had 90% lower risk (RR=0.10; 95%CI:0.01-0.68) of nutritional therapy dropout compared to those who lost <10% of weight, controlling for sex and age. Conclusions: A great proportion of patients undergoing bariatric surgery did not meet the international criteria. A greater loss of weight during the first month was associated a lower dropout rate during nutritional therapy. / Revisión por pares