If you are in the "my dog is a carnivore" group
I was referring to choosing a brand of dog food. Yes, all dry dog kibble foods have fillers and preservatives. Otherwise they wouldn't be in convenient shaped kibbles in bags that can be stored at room temperature for months at a time. If you want to go to the extreme and forget dog food, then feeding a home prepared diet would be best. I made the very basic distinction to show that there are two basic and different views on dog food: those that feel dogs have evolved over time into omnivores because of living with people and those that feel that despite living along side people have kept their original carnivorous nature and physiology. With the omnivorous philosophy, the human induced evolution, it is appropriate and cost effective to choose a dog food that is lower in meat derived protein and higher in carbohydrates and plant derived protein such as corn and rice. People of this following typically will take the stance that excess protein is not only wasteful financially, but also biologically because dogs will excrete the excess protein they don't metabolize. If this is the case, feeding Kirklands is great. Those that feel dogs have not deviated from their original design (BARF and raw people typically fall into this category) will feed a higher protein diet. Orijen dry dog food was designed to mimic the raw diet because they feel it is more biologically appropriate to feed a high meat based protein diet. Older dogs don't always fit the mold, especially if they are dealing with kidney issues. Dogs already dealing with kidney insufficiency wont tolerate high protein well because their kidneys can't filter as well as they used to. Some older dogs just have hard time tolerating anything, but maybe that's because of the foods we are feeding dogs nowadays... dry dog food isn't a very natural choice no matter what brand you feed.The only way to really do that is to feed a raw all meat diet. All processed dog food has filler in it, it's a matter of what kind and how much. I also find with older dogs the higher protein is harder on them, in his last year my oil dog I ended up cooking for him as he couldn't handle much protein at all...