The objective of this study is to investigate whether intake of a diet with a high content of butyrate (from dairy fat) can affect blood FIAF concentration compared to a control diet. Further to examine whether high intake of inulin (a prebiotic) can increase the proportion of butyrate-producing bacteria in the gut and thereby affect blood FIAF concentration. In addition, the correlation between FIAF blood concentrations and resting energy expenditure, blood lipid profile and gut microbiota composition will be investigated.