Introduction and aims: In obese patients, long-term weight loss maintenance remains challenging. Identifying factors predicting adhesion to lifestyle therapy and weight loss would help optimizing obesity management. Aims: to identify predictive factors of weight loss after one year of medical therapy in obese patients (primary) and predictive factors of drop-out during the year of therapy (secondary). Methods: In this retrospective study, obese patients consulting for the first time in an obesity specialized center were included. All patients fulfilled the criteria for obesity surgery and were managed to change their lifestyle by following a 1-year therapeutical education program based on intuitive eating. Significant weight loss was defined by ≥5 % after 1 year. Patients were considered as dropouts, i.e. absence of adhesion to therapy, once they missed one consultation without informing the unit. Stepwise multivariable analyses determined the predictive factors. Results: Of the 310 patients (mean age, 44.5±11.9 yr, 79% women) included, 155 (50%) maintained their follow-up at 1 year and 37 (24%) experienced weight loss ≥5%. Male gender (odds ratio (OR)=6.25 [95% confidence interval, 1.78; 21.92], P=0.004), ≥5 consultations with intuitive eating (OR=3.69 [1.14;11.87], P=0.03), and tobacco addiction (OR=0.18 [0.04; 0.82], P=0.03) were associated to weight loss ≥5%. Older age (OR=0.97 [0.95; 0.99], P=0.014), physical activity (OR=0.11 [0.05; 0.24], P<0.0001) and the patient desire for obesity surgery (OR=0.22 [0.12; 0.41], P<0.0001) were associated with a better adhesion to therapy. Conclusion: The identified predictive factors would help identifying the patients with the greater chance of losing weight and adhering to therapy. Offering more therapeutic education sessions should increase therapy success in obese patients fulfilling the criteria for obesity surgery.