Perspective. Precision Nutrition at a Crossroads: From Biological Prediction to Contextual Implementation

Precision nutrition has substantially reshaped nutritional science by demonstrating that individuals can respond differently to identical dietary exposures. Advances in genomics, metabolomics, proteomics, microbiome research, wearable technologies, digital health, and artificial intelligence have improved our ability to characterize biological heterogeneity and predict individual responses to diet. However, demonstrating such variability does not necessarily result in nutritional strategies that provide clinically meaningful benefits beyond established evidence-based care. A critical distinction should therefore be made between precision nutrition as a discovery science, which has convincingly established interindividual heterogeneity in dietary responses, and precision nutrition as an intervention science, which must demonstrate meaningful incremental value over dietary approaches already supported by clinical evidence. Despite increasingly sophisticated technologies and predictive models, evidence of consistent improvements in long-term health outcomes, cost-effectiveness, scalability, and equity remains limited. In this Perspective, we argue that precision nutrition has reached a critical crossroads. We distinguish prediction of individual responses, which is only one route to precision nutrition, from treatment-effect heterogeneity, treatment selection and clinical utility. We then propose contextual precision nutrition as a translational framework that integrates biological responsiveness with the behavioral, psychological, social, cultural, economic, and environmental determinants of dietary behavior. Rather than claiming novelty for these components, the framework integrates them into a decision logic that asks whether biological information improves the selection of a dietary strategy beyond routine information and established care, and how that strategy can be delivered and sustained. It complements population-based dietary recommendations by refining their implementation and maximizing adherence and real-world effectiveness. Ultimately, the success of precision nutrition will be determined not by the sophistication of its predictions but by its ability to translate biological knowledge into interventions that are clinically effective, scalable, equitable, and sustainable, thereby improving both individual and population health.