Purpose of Review <p>GLP-1 receptor agonists (GLP-1RAs) have become central therapies for obesity and metabolic disease. Although these agents produce substantial and sustained weight reduction, emerging clinical observations suggest that chronic therapy may be accompanied by changes in lean mass trajectory, reduced protein intake, and micronutrient insufficiency. This review examines metabolic adaptations during GLP-1RA therapy and their implications for nutritional and redox homeostasis.</p> Recent Findings <p>GLP-1RA therapy maintains receptor signaling while reducing nutrient inflow, creating a physiological state of chronic energy flux constriction. Under these conditions, systemic metabolism increasingly relies on lipid-derived substrates and elevated oxidative throughput. When oxidative demand approaches the regenerative capacity of nicotinamide adenine dinucleotide (NAD⁺)/ nicotinamide adenine dinucleotide phosphate (NADPH; reduced form)-dependent buffering systems, several constraint-sensitive metabolic processes—including NAD⁺ partitioning, amino acid–dependent antioxidant–anabolic coupling, micronutrient-dependent enzymatic activity, and bile acid–mediated absorption—may become functionally limiting.</p> Summary <p>Integrating emerging mechanistic and clinical observations, this review synthesizes current evidence from a metabolic flux perspective. This approach highlights how nutritional substrates and metabolic cofactors may influence physiological resilience during sustained pharmacological weight reduction. Clarifying these interactions may inform clinical monitoring strategies and nutritional management during long-term GLP-1RA therapy.</p>