Updated project metadata. This dataset was obtained from the authors of Starke et al. (2020, Journal of Proteomics 222: 103791, https://doi.org/10.1016/j.jprot.2020.103791). Sample labels: 1 - High fiber diet inoculum 2 - High protein diet inoculum 3,4,5 - High fiber + unlabeled water 6,7,8 - High protein + unlabeled water 9,10,11 - High fiber + 25% of 99.9 atom% D2O 12,13,14 - High protein + 25% of 99.9 atom% D2O 15,16,17 - High fiber + 25% of 99.0 atom% H218O 18,19,20 - High protein + 25% of 99.0 atom% H218O Direct quote from the original article describing the dataset. “…the impact of specific diets on a defined microbial community derived from a human fecal sample was to be determined. The defined community was chosen to provide a stable in vitro setup that could be useful for future microbiome research. Briefly, the microbial community was grown in a heavy fiber and a heavy protein diet in addition to 25% heavy water, either as D2O or H218O. A dosage of 25% isotopically labeled water was chosen by trial-and-error to yield sufficient incorporation into protein but avoid the reduction of activity of individual organisms. A difference in growth medium formulation, representing a high-fiber diet and a high-protein diet, was utilized to evaluate shifts in microbial activity. We chose to assess these diets because high-protein, low-carbohydrate interventions represent a popular weight-loss strategy and because we expected a strong effect on the synthesis of amino acids by this comparison. After an incubation time of 12 h, the proteins were analyzed for label-free quantitation (metaproteomics) and incorporation of isotopes (protein-SIP), each in triplicates….”