Aim: The purpose of this pilot study is to investigate whether the metabolic typing diet warrants further investigation as a tool to design dietary regimes in professional rugby union players. The authors of the metabolic diet report that differences in metabolic make-up will alter dietary regimes that should be recommended to athletes who come from varied genetic backgrounds, such as rugby. However, most of the current research in the sport nutrition arena has been completed on Caucasioan cyclists and may nor be applicable to a power based team sport such as rugby union.

Data Source: Five professional rugby players took part in this pilot study. The tests performed include basal metabolic rate measured for 20 minutes at steady state using a metalyzer; fasted blood pH using automatic cartridges; glucose challenge test based on the blood glucose response to a glucose/potassium solution and the metabolic typing questionnaire.

Outcome Measure: The results from the questionnaire, basal metabolism, fasted pH and glucose challenge test were converted into a category as defined by the metabolic typing diet to investigate whether there was agreement.
Results: The five players were categorised as ‘mixed oxidizers’ according to the questionnaire. The results from the laboratory tests and the questionnaire differed. The basal metabolic rates resulted in zero ‘mixed oxidizers’, categorised based on the metabolic rate and four subjects based on the respiratory quotient values, the fasted pH results rated none of the players as ‘mixed oxidizers’ and the glucose challenge test rated three players as ‘moderate fast oxidizers’, which is close to mixed oxidizers.

Conclusion: Results suggest that at least in Caucasian professional rugby players the metabolic typing diet questionnaire results did not accurately reflect the actual metabolic processes in a usable way.