|I'm hesitant to recommend a change if the Iams is really working for you- while it's better in theory to avoid those ingredients you mention, you don't want to hurt your dog for the sake of a theory.
From the ingredient list:
Corn Grits, Brewer's Rice, Chicken By-Product Meal, Chicken, Fish Meal, Dried Beet Pulp, Chicken Flavor, Dried Egg Product, Chicken Fat (preserved with mixed Tocopherols, a source of Vitamin E), Brewer's Dried Yeast, Calcium Carbonate, Potassium Chloride, Fructooligosaccharides, Monosodium Phosphate, Vitamins (Vitamin E Supplement, Ascorbic Acid, Vitamin A Acetate, Calcium Pantothenate, Biotin, Thiamine Mononitrate [source of Vitamin B1], Vitamin B12 Supplement, Niacin, Riboflavin Supplement [source of Vitamin B2], Inositol, Pyridoxine Hydrochloride [source of Vitamin B6], Vitamin D3 Supplement, Folic Acid), Fish Oil (preserved with mixed Tocopherols, a source of Vitamin E), Sodium Hexametaphosphate, Choline Chloride, Flax Meal, DL-Methionine, Minerals (Ferrous Sulfate, Zinc Oxide, Manganese Sulfate, Copper Sulfate, Manganous Oxide, Potassium Iodide, Cobalt Carbonate), Ethoxyquin (a preservative), Rosemary Extract
That actually doesn't look that bad to me. Corn is really not such a bogeyman as it's made out to be, and while it does contain byproducts, they're not the only animal protein source. Plus it's all from named animal species.
I think the magic ingredients here are the beet pulp and the fructooligosaccharides. (Hoo boy, I'm only go to type that once!) The beet pulp is a source of fiber for firming up the stool as Jake mentioned. The FOS is a type of carbohydrate that is indigestible to most animals, (in other words, "fiber") but the gut bacteria LOVE it. It stimulates activity of beneficial bacteria in the intestines which slow intestinal transit, bulk/firm up the stool, and increase mineral absorption.
Likely those ingredients are why this food is helping your dog. You could probably feed a different food if it had a similar nutritional analysis and also contained prebiotic fiber (either a refined form like FOS or from a whole-food source like chicory root.) Or give a standalone prebiotic supplement.
Edit to recommend a specific food- Acana, made by Champion Pet Foods of Canada is moderately high in fat/protein for small, firm stools, and contains natural sources of prebiotic fiber, like chicory root and dandelion greens. Champion's other product is Orijen dog food, which is much higher in protein, lower in carbs/fiber, so I'm not sure it would be appropriate. They don't make a canned version of Acana, unfortunately. If you only use canned as a small amount of the total diet (as a sauce or topper with the dry) you could use any high-quality brand. Or just use plain broth or unsweetened yogurt on the food instead.
Edited by author Mon Dec 26, '11 11:46pm PST