Introduction The escalating prevalence of obesity presents a multifaceted challenge involving genetic, environmental, and behavioral factors, with significant public health implications. Photobiomodulation (PBM) may positively influence metabolic activities in adipose cells and regulate inflammation, potentially impacting obesity. Methods A systematic review and meta-analysis were conducted to assess the effects of transabdominal PBM treatments in preclinical and clinical obesity studies, covering a range of physical, psychological, and physiological variables. Research articles were sourced from PubMed, Web of Science, ScienceDirect, and Scopus databases. Following the inclusion and exclusion criteria, a total of 24 studies, comprising 1041 patients, and 100 mice were incorporated. R software was employed for conducting meta-analyses, and calculating effect sizes between experimental and control groups. Results In human models, significant discrepancies were revealed in waist circumference (Z = -2.16; p = 0.031), hip circumference (Z = 2.11; p = 0.035), insulin levels (Z = 2.11; p = 0.035), and triglycerides (Z = -2.4674, p = 0.0136). In animal models, significant differences were observed in epididymal adipocyte area (Z = -5.6930; p < 0.0001), triglycerides (Z = -2.0254; p = 0.04848), and glucose area under the curve (AUC; Z = -6.4112; p < 0.0001). Conclusions This study underscores the necessity of considering diverse wavelengths in PBM research, particularly within the realm of obesity, and emphasizes the imperative for further investigations to comprehensively elucidate PBM mechanisms and applications. The exploration of innovative therapeutic approaches unfolds novel avenues in the pursuit of comprehensive strategies to address obesity and its underlying determinants.