Abruptly switching dog food is generally not recommended, as this can lead to digestive problems such as vomiting or diarrhea, stomach upset, and decreased appetite. Instead, gradually switch your dog to the new food for about a week. Abruptly switching dog food is generally not recommended, as this can lead to digestive problems such as vomiting or diarrhea, stomach upset, and decreased appetite. Instead, gradually switch your dog to the new food for about a week.