<p>The concept of periodised nutrition is well-established within performance nutrition support to appropriately fuel elite athletes while maximising the adaptative response from training. Despite this, there may still be little planning and integration of training prescription and nutrition between the performance nutritionist and multi-disciplinary team. Consequently, the aim of this case study was to (1) propose a ‘Periodised Nutrition System’ which can be utilised by performance nutrition practitioners when working with athletes, through amalgamating previously published literature, tools, and approaches in the literature; (2) discuss how this can be administered in practice, collaborating with the coach, multidisciplinary team and athlete; (3) present a case study of the proposed ‘Periodised Nutrition System’ and its utilisation with a world class swimmer leading into the 2024 Paris Summer Olympic Games. The ‘Periodised Nutrition System’ presents different ‘performance plates’, quantities of different foods to fit into the ‘performance plates’ to aid recipe development, and how they may practically fit into an athlete’s training periodisation alongside theoretical rationale. The case study demonstrates a ‘real world’ scenario of its utilisation with an elite swimmer, transitioning through three separate performance goals while reducing body mass by 1.9 kg, sum of eight skinfolds by 20.1 mm, predicted fat mass by 2.6 kg and an increase in predicted lean mass by 0.6 kg over a six-week mesocycle. The study highlights that the ‘Periodised Nutrition System’ enables the practitioner to develop a structure to their support, aligning nutritional strategies with the training periodisation of the athlete, allowing for an individualised approach, specific to the athlete’s performance goal(s) and the desired adaptation of a training session.</p>