Hi John B:
Since dogs do not technically have a carbohydrate requirement, I would say that a diet with little to no carbohydrates would be best for your dog. Corn, wheat, potatoes, rice, squash-all are heavy in carbohydrates and therefore unnecessary unless you have a dog with a high metabolism and you need to add calories to help them maintain weight. Fat is an essential nutrient to a dog but those suffering from sensitivity to high fat levels and/or pancreatitis may have issues, so it’s not really very easy to say one is better than another across the board.