[Precision nutrition: handle with care.].

Diet is a fundamental risk determinant for the majority of chronic diseases in the western world. Precision nutrition aims to tailor nutritional interventions, through the availability of new technologies in the "omic" area. This knowledge has enormous potential, but there are currently no validated results in the clinical setting. Precision nutrition is currently a hypothetical approach to predicting, preventing and treating some of the major chronic diseases in the individual. Therefore, extreme caution is needed before announcing the beginning of a new era.