I found some sources online to help you, like CatInfo.org's food chart and Tanya's FelineCRF.org food lists. Nonetheless, whilst pretty helpful and excellent, I found these lists were not just current, and a lot of the foods cited as very low phosphorous on those lists weren't down below 0. cprcheeta: https://pet-clippers99754.buyoutblog.com/37801927/not-known-details-about-royal-canin-kitten-sterilised