I would think that most high quality, non vegetarian dog foods will not contain soy or navy bean (this one would be a rare ingredient even in vegetarian kibble!).
For lowfat foods, I would look through DFA’s list of lowfat foods, particularly the grain free ones. For dry foods without white potato, InkedMArie has posted here in forums a list of grain-free and white potato free foods and I would cross check it.
High carb foods, more than high protein/fat foods, show in studies to put more weight on dogs. So I would keep that in mind. But even among the reduced carb/higher protein grain free foods, there are some that are low fat. Two that come to mind are Honest Kitchen’s Zeal and Wellness Core’s reduced fat formula.
