The completion gap framework: age-associated weight gain as passive convergence between meal completion and energy demand

Abstract Age-associated weight gain is commonly attributed to behavioral or metabolic changes. We propose the completion gap framework, in which meal-completion requirements and physiological energy demand are only partially coupled. Persistent mismatch between these variables produces gradual weight gain until a higher equilibrium body weight is reached. This systems-level perspective integrates existing regulatory models while generating experimentally testable predictions for aging, obesity, and nutrition.