Macronutrients, Lifestyle, and Cognitive Ageing: Beyond Binary Interpretations

Abstract

Inconsistent associations between macronutrient composition and cognitive ageing often reflect binary framings that ignore context. By binary interpretation we mean dichotomous framings that overlook dose response, substitution among macronutrients, and heterogeneity by diet quality, energy balance, and metabolic or genetic risk. We propose a context-informed framework that prioritises dietary quality, sets protein and carbohydrate targets by metabolic risk and body composition, and integrates nutrition with activity and sleep to support cognitive reserve. We distinguish model-specific findings in repair-deficient mice from population-
level evidence linking carbohydrate quality and prudent dietary patterns with healthier cognitive ageing. We outline pragmatic trials with prespecified cognitive outcomes, explicit substitution within high-quality patterns, risk stratification, adherence measurement, and clear reporting of energy balance. Macronutrient targets should be treated as context-dependent substitutions and tested accordingly.