Liraglutide is a glucagon-like peptide 1 receptor agonist which acts through peripheral and central receptor pathways affecting food intake. Preliminary identification of responder patients represents a crucial point to reduce an inappropriate exposure to the drug and the health expenditure. The primary endpoint of our study was to identify predictors of liraglutide efficacy in the short term follow-up. The secondary endpoint was to evaluate the treatment efficacy stratified by the underlying psychiatric disorder. We evaluated a cohort of 100 patients (77 females, 23 males, mean body mass index 38.6 ± 3.2 kg/m) who were evaluated at baseline, and after 1, 3, and 6 months of treatment. Liraglutide efficacy was defined by a weight loss ≥5% of initial weight. Sociodemographic/metabolic parameters, food intake, smoking habit, and physical activity were correlated with liraglutide efficacy. There was a significant weight loss after 1 month of therapy, as well as after 3 and 6 months when compared to the baseline (<.0001; 27%, 45%, and 57% of patients showed a weight loss ≥5%, respectively). No difference was found in weight loss between the 3 groups of patients (with binge eating, with/without psychiatric disorders). The weight loss at 1 month was the only predictor of a positive response to the treatment. Our results confirm the efficacy of liraglutide even at a lower dose than conventional. The early response to the drug seems to be a good predictor of long-term efficacy and it might be useful in clinical practice to identify patients in whom liraglutide may induce a significant weight loss. = body mass index; = European Medicine Agency; = Food and Drug Administration; = glucagon-like peptide 1 receptor agonist.