You might want to read this study, Primary prevention of colorectal cancer at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2393072/pdf/bullwho00054-0089.pdf and this study http://www.biomedcentral.com/1746-6148/9/201, Impact of diets with a high content of greaves-meal protein or carbohydrates on faecal characteristics, volatile fatty acids and faecal calprotectin concentrations in healthy dogs. There are also older research studies which you can review to understand the correlation between dietary fat and feacal pH.