Ever wondered why dogs get bloat? It's the Starch in their diet!
Most pet foods are grain based, even gluten free ones are either based on rice or potato.
These are very high in starch content. Amylase is what is needed to digest starch. Dogs do not produce amylase in their saliva, and only produce a very small amount from their pancreas.
The starch lines the stomach wall, having a negative effect on the pH of the hydrochloric acid in the stomach reducing the dogs ability to digest food. The only way starch can be broken down other than the very small amounts of amylase produced by the pancreas is via microbial fermentation in the gut.
This fermentation process produces large quantities of gases, which promote bloat & further reduces the ability of the dog to digest other food ingested.
Therefore the answer is simple, if you don't want to risk bloat, don't feed starch.