Do not be confused or fooled by dry dog foods that advertise themselves as being “grain free” and therefore supposedly healthier. Those foods have to use some sort of carbohydrate source to hold the dough together that becomes kibble- and many are using potatoes, which are not just a starch (also known as a carbohydrate) but are also high on the glycemic index (for example, diabetic people need to stay away from potatoes).
All the same, starchy vegetables like sweet potatoes and white potatoes are all excellent sources of healthy carbohydrates, too, but again you want to make sure they are whole versions of those foods, and not the discarded, damaged leftovers of food that was made for people. Sometimes you will see “pea” or “pea flour” used in place of other carbohydrate sources, and that can be a good ingredient, too. But do not be confused into thinking that there is inherently something wrong with grain in dry dog food – quite the contrary.
Whole, gently processed grains are excellent sources of energy in your dog’s food. Of course, there is an understandable push-back about the heavy presence of corn in bagged dog foods – usually found in the supermarket brands or the lower cost/lower quality foods (you can read more on that topic in THE DOG BIBLE or on my website in other blogs I have written or Q&A’s posted there – where I say that corn has become a four-letter word in the pet food world).
However, there are many grains that are terrific carbohydrate sources as long as they are not sourced from the broken-down remnant components of those ingredients from the human food production process. You want to choose dry dog food that utilizes whole grains like rice or brown rice (as opposed to “brewer’s rice), or whole ground barley or oatmeal – not flour made of these ingredients or fragments of these carbohydrate sources.