With the experience of the COVID-19 pandemic and the importance of health is the renewed awareness, the relationship between food and health is attracting attention. In particular, advances in analytical techniques have revealed the biological functions of metabolites produced from fatty acids in dietary oils, and the function of dietary oils in relation to health has been elucidated. In this presentation, I would like to introduce recent findings about the possibility of precision nutrition based on the individual differences in the regulation of function and health maintenance/promotion through the metabolism of dietary oils by the host and commensal bacteria.