Background The evidence supporting the benefits of early exercise in post-bariatric patients is growing. This study analyzed the effects of early exercise (1-week post-bariatric surgery) on body composition in patients with overweight and obesity 1 month after surgery. Methods Thirty patients (age 36.5 +/- 12.3 [range, 18-65] years; body mass index [BMI], 36.2 +/- 12.3 kg/m(2), range, 29-48) who underwent laparoscopic sleeve gastrectomy for bariatric surgery were instructed to participate in an exercise training program initiated on day 3 post-surgery and to follow a recommended protein intake of 60 g/day. After 1-month post-surgery, patients were stratified into those who adhered to exercise recommendations and those who did not. Pre- and post-differences in total weight loss (TWL), skeletal muscle mass (SMM), fat mass (FM), and visceral fat mass (VFM) were compared. Results TWL, SMM, and FM loss were similar between non-adherent and adherent subjects (10.2 +/- 3.5 kg and 11.9 +/- 3.6 kg; p = 0.2; 2.9 +/- 1.0 kg and 3.2 +/- 1.2; p = 0.2; 6.2 +/- 2.1 kg and 7.5 +/- 3.6 kg; p = 0.2, respectively), whereas VFM was markedly reduced in the adherent group (29.9 +/- 18.2 cm(2 )vs 14.6 +/- 9.4 cm(2); p = 0.01) compared to the non-adherent group. When the group was divided according to adherence to exercise and protein intake or non-adherence to both conditions, there was a significant difference in TWL, FM, and VFM losses (p < 0.05). In contrast, no differences in SMM were found. Conclusions Early exercise training accelerated visceral fat mass loss during the initial recovery period in patients after bariatric surgery. Additionally, adherence to daily protein intake recommendations can increase total body weight and fat mass loss.