Introduction: clinical practice guidelines recommend considering pharmacological treatment of obesity only as a complement to lifestyle modification. Drugs alone are usually ineffective in the long term after discontinuation, so pharmacological weight loss strategies should always be accompanied by lifestyle modifications. Objective: to analyze the changes in weight, body mass index and body composition by means of electrical bioimpedance after a 32-week treatment with liraglutide in patients with obesity, associated or not with a food education program. Materials and methods: the study involved 68 patients who were randomly divided into 2 groups. One group received treatment with liraglutide 3.0 mg/day along with individual dietary education, and the other group was treated with liraglutide 3.0 mg/day and standard medical follow-up for 32 weeks. The data collected were weight (kg), height (m) (Seca® brand), body mass index (kg/m2) and body composition using multifrequency bioimpedance (SECA 112® brand). The variables were analyzed at the beginning and at the end of the treatment. Results: after 32 weeks of treatment, both study groups lost weight significantly. The group treated with liraglutide and individual dietary education had a reduction of 8.77 kg (9.08 %) (p < 0.001) and the group treated with liraglutide without education had a reduction of 3.55 kg (3.45 %) (p < 0.001). The BMI of the participants treated with liraglutide and education decreased by -4,04 kg/m2 (10.35 %) (p < 0.001) and in the group without education it decreased by -3.22 kg/m2 (8.30 %) (p = 0.003). In the educated group, fat mass decreased by -7.65 kg (15.89 %) (p < 0.001), although skeletal muscle mass also decreased by -1.62 kg (6.8 %) (p < 0.001). In those treated with liraglutide without education, a reduction in fat mass and skeletal muscle mass was also observed - fat mass by -4.72 kg (9.43 %) (p < 0.001) and skeletal muscle mass by -0.17 kg (0.70 %) (p < 0.001). Differences were also observed between groups, observing a greater reduction in weight, BMI, fat mass and skeletal muscle mass in the group with liraglutide and education compared to the group without education, although these differences were not statistically significant. Conclusions: dietary education associated with liraglutide treatment may contribute to increasing weight and fat mass losses. However, it was also associated with an unwanted loss of skeletal muscle mass, probably related to the greater intensity of weight loss, which will have to be reversed in future therapeutic approaches. Habit modification through multidisciplinary treatment, including nutritional education, combined strength and resistance exercise, and cognitive-behavioral therapy, could be an effective way to treat obesity and maintain weight, body composition, and adherence to a lifestyle.