As we enter the ‘genomics’ era, scientists and practitioners are becoming more aware of the role that an athlete’s genes may have on their health, training, and performance. This chapter therefore aims to develop a broader understanding and appreciation of the role that genetics plays in sport and exercise performance, and how a personalised nutrition approach may be utilised to support individual health and performance, and to optimise recovery. Scientific evidence on nutrigenomics (“the study of interaction of dietary components with the genome and the resulting proteonomic and metabolomic changes”; Subbiah, 2007) and nutrigenetics (the study of “gene-based differences in response to dietary components”; Subbiah, 2007) is still developing, yet it is clear that the influence of nutrition and lifestyle on genetic expression is a complex, personalised, subject.

The key objectives of this chapter are to provide an overview of ‘personalisation’, biochemical individuality, nutrigenomics, nutrigenetics, and the role of genetics on health and human performance. It is not possible to explore every such genetic influence; instead, research around key influences (single nucleotide polymorphisms [SNPs]) are explored, and then contextualised within a case study about a professional triathlete who pursued personalised nutrition and lifestyle support.