Dogs Natural Magazine and Science Mag have a wonderful article about dogs and starch, I will post them down below. The summery for the article is that in order for wolves to become dogs they had to adapt to what humans ate. Since humans primary ate a starch rich diet, our dogs must have too! This adaptation in their food also genetic mutated the dogs, allowing for better starch digestion!
The study which both articles refer too, was conducted by a group of evolutionary geneticist from Uppsala University of Sweeden. In comparing the DNA of 12 wolves from around the world and 60 dogs with diverse genes they found that dog had between 4 to 30 copies of the digestive enzyme amylase, which is used to break down starch. Wolves where only found to have 2 copies. They then compared the expression of that gene in dogs and found a 28 fold increase in the dogs. Not only that but the gene MGAM which codes for maltase which is another important factor in the digestion of enzymes, is longer in dogs which is what is found in herbivores such as cows and rabbits. This is shocking and wonderful, this puts dogs firmly in the omnivore category meaning they can thrive on just plants or both plants and meat.
So that tells us a few things, but truth is overwhelming dogs like humans are meant to eat starches, they digest them better and seem to be made for it. Now this article ends on a strange note, because after point out all this research it says that this study fails to prove anything?! Which is the authors way of saying that this empirical research does not conform to his/her personal belief on how dogs should be feed and therefore "fails". This is nonsense we now know that dogs are far better at the genetic level of digesting starches than their wolf counterparts.
The Science mag article concludes with Robert Wayne, an evolutionary biologist at UCLA, who studies dogs. He is often contacted by dog owners who want to know how they feed their dogs and if they should primarily be feed a meat based diet. To which he says, "This (study) suggest no, dogs are different from wolves and don't need a wolflike diet," "They have co evolved with humans and their diet." This is how you draw a proper conclusion to such a comprehensive study, if dogs where meant to eat like wolves then they would still be wolves.