A Narrative Review of Factors Predisposing to Weight Gain and Weight Maintenance

Abstract

Background: The global increase in body weight represents one of the most significant public health challenges of the modern era, affecting populations across all socioeconomic levels and geographic regions. The escalating prevalence of overweight and obesity has contributed substantially to the global burden of non-communicable diseases, including cardiovascular disease, type 2 diabetes mellitus, several cancers, and musculoskeletal disorders, while simultaneously reducing quality of life and increasing healthcare expenditures. Although weight gain has traditionally been explained by the energy balance model, this framework alone fails to account for the marked inter-individual variability in weight trajectories. Current evidence indicates that body weight regulation is a complex and dynamic process shaped by the interaction of biological predispositions, behavioral and lifestyle factors, psychological influences, and environmental and socioeconomic conditions. Biological mechanisms, including genetic variability, hormonal regulation of appetite, and adaptive thermogenesis, generate strong physiological pressures that favor weight regain following weight loss. Methodology: This narrative review synthesized current evidence on the multifactorial determinants of weight gain and long-term weight maintenance. A comprehensive literature search was conducted in PubMed/MEDLINE, Web of Science, and PsycINFO using combinations of MeSH terms and free-text keywords related to obesity, weight regulation, predisposing factors, and biological, psychological, behavioral, and environmental mechanisms. Additional sources were identified through citation tracking and consultation of grey literature from authoritative public health organizations. Relevant peer-reviewed studies and reports providing mechanistic insight or integrative perspectives were selected through iterative screening. Due to heterogeneity in study designs and outcomes, findings were synthesized narratively and organized within a socio-ecological framework to elucidate the complex and adaptive nature of body weight regulation. Results: Research demonstrates that weight regulation is a complex adaptive system; biological factors (e.g., genetic predisposition, adaptive thermogenesis) establish susceptibility and create a persistent physiological drive for weight regain; behavioral factors (e.g., consumption of ultra-processed foods, physical inactivity, inadequate sleep) are the main mediators of energy imbalance; psychological factors (e.g., stress, emotional eating, self-regulation) critically influence behavioral choices. In the end, these individual-level factors function within potent obesogenic environments and socioeconomic contexts that encourage overconsumption and sedentarism. Conclusion: Simple, one-level interventions are insufficient for effective obesity prevention and management techniques. Success necessitates integrated, multi-level strategies that combine systemic public health policies intended to transform obesogenic environments with individualized assistance for behavioural and psychological transformation. Developing compassionate and long-lasting solutions requires an understanding of this intricate etiology.