I can only go by my experience, I have changed dog foods and the only adverse reaction I observed was a loose stool or two.
But, the recommendation is that you go 1/2 and 1/2 with the old and new food for a few days, mix them together.
The thing about higher quality food is that they don’t need as much of it, my 9 pound poodle mix has 1/4 cup of Nutrisca salmon and chickpea dry twice a day with about a tablespoon of cooked chicken or lean meat added.
Maybe a bite of kibble or meat as a snack once or twice a day.
I get the boneless chicken breast and sandwich steak in the reduced price section of my local market. After you cook it up, you can freeze daily servings in small freezer bags.
I find this to be cost effective. I am leery of all kibble, I try to keep the kibble just as a base, 20%-30% of the diet.
