In the past decades, extensive usage of omic technologies applied to nutrition has led to the concept of personalised dietary recommendations. It is now widely accepted that gene–diet interaction is a complex, bidirectional mechanism: food components can modulate the flow of genetic information by regulating genes at transcriptional, translational and post-translational levels, whereas the individual's genotype determines specific responses to nutrient intake. Genetic variants (that represent the focus of nutrigenetic studies) influence the metabolism of almost all macro- and micronutrients, thus differentially impacting on human health. Although still a young field of research, nutrigenetics appears to be a promising tool for monitoring susceptibility to chronic pathologies, as well as for designing personalised nutrition in order to prevent (or eventually treat) the most common Western diet-associated diseases.