In bariatric surgery, inflammatory biomarkers predict outcomes. Limited research on complete blood cell (CBC) markers stresses the need for correlation study. This research explores links between CBC inflammatory markers, body changes, and fatty liver grades in Iranian bariatric patients. This retrospective longitudinal study examined 237 bariatric surgery patients who satisfied the inclusion criteria and were deemed eligible for participation. These criteria encompassed patients who had undergone sleeve or mini-bypass surgery and were aged between 18 and 65 years. The study gathered demographic data, pre and post-surgery changes in CBC inflammatory biomarkers [neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR), mean platelet volume (MPV), MPV-to-platelet count ratio (MPV/PC), and red cell distribution width (RDW)] and fatty liver grades. Additionally, it recorded pre and post-surgery changes in body composition, such as weight, muscle mass (MM), fat mass (FM), and fat-free mass (FFM). The pre-surgery RDW marker significantly associated with FM changes, highlighting its predictive nature. While no significant association was found between changes in patients' fatty liver grade and baseline marker values, it's worth noting that individuals with higher MM at 3 months achieved a fatty liver grade of zero. Also, at 6 months, higher FFM and MM were also associated with reaching a fatty liver grade of zero. While the retrospective design of this study limits its findings to existing clinical data, future prospective research should collect additional samples, extend the observation time, and examine the long-term predictive value of these markers.