The concept of ‘personalized’ or ‘precision’ is nowadays very widely used in the medical field since the Precision Medicine Initiative was launched in 2015 in the United States. Another recent trend is the use of individualized data about a person to customize dietary therapies, such as recommendations, materials, and services, to help them achieve better outcomes through individual and genetic-based strategies, sometimes referred to as personalized or precision nutrition. Personalized nutrition has progressively become truth due to the advancements in the genomics, transcriptomics, proteomics, microbiome, metabolomics, and data technology. Personalized nutrition can be used for illness treatment by means of specialized nutritional therapies, such as a non-gluten diet for those with celiac disease and a dairy-free diet for dairy intolerance, or avoiding dietary phenylalanine for phenylketonuria. Further, various studies are being carried out on the application of personalized nutrition for obesity, metabolic syndrome, certain cancers, and type 2 diabetes mellitus. However, the area of personalized nutrition continues to face a number of problems, including a lack of effectively organized research investigations with consistent results, and expensive and advanced technologies for collecting and studying DNA, gastrointestinal bacteria, and food intake of people in general. Personalized nutrition promises to embrace and harness new technologies and integrate them into dietary interventions, but it is expensive and has less impact on population health, and therefore it requires collective efforts from an ethical and legislative perspective in order to implement it through successful strategies, laws, and population-centered approaches.