FIG 2.

Many resources relevant to microbial growth and function are naturally sourced from the typical human diet. Identifying what specific resources drive microbial differences in humans whose diets vary is a complicated endeavor, however. Here, we show how the USDA MyPlate-recommended diet components include various microbially relevant resources such that changing diet broadly may not allow researchers to ascribe causality to microbial changes. Further theory on limiting resources and controlled experiments isolating individual aspects of diet are necessary to develop a dynamic range of manipulations and to understand the degree to which host physiology modulates microbial responses to diet.