This is good advice only if you are putting processed junk food on the family's dinner table. But if you are health conscious, trying to feed your family a variety of fruits, nuts, vegetables, whole grains, dairy products and meats, such food can only benefit.
Thousands of cats have suffered from a heart disease called dilated cardiomyopathy. This disease resulted from a deficiency of the amino acid taurine in commercial pet foods. No, these were not cheap inferior generic foods. They were premium diets which had been "proven" to be "100% complete and balanced" through feeding trials, laboratory analyses and digestibility studies.
If cat owners had occasionally fed portions of organs and meats, the deficiency would have never resulted.1 Untold thousands of cats would have been spared suffering, disease and death, and owners spared grief and medical costs.
The fact that manufacturers now add synthetic taurine to diets does not really solve the underlying logical problem of reliance on commercial products being "100% complete." Again, no one knows what "100% complete" is. Must we continue to learn the hard way?
Taurine deficiency is just the tip of the iceberg. Other recent discoveries include potassium deficiency, carnitine deficiency, zinc deficiency, riboflavin deficiency and chloride overdose. There is every reason to believe that many chronic degenerative diseases such as arthritis, obesity, heart disease, cancer, immune disorders, allergies, and skin, eye and ear infections can often be related to chronic malnutrition.2 Subtle deficiencies cast a long shadow on health and cannot be detected in short-term feeding trials. Rather, they incubate over the lifetime of the animal to crop up in later years when little can be done to resolve the problem or (convenient to the perpetrators) identify the underlying cause - "100% complete" pet foods.*
Not only do manufacturers imply that their foods are human quality, but they then caution pet owners against feeding table scraps or grocery non-processed foods. They can do it, but you can't?
Home cooking and feeding is just not good business. It runs contrary to the ultimate objective of marketers - 100% consumerism. We, the public, are to be mere profit centers - passive, compliant, uncritical, dependent and unthinking. Food industrialists will engineer, grow, cook and deliver your food, and, just like mom and dad, tell you what is best and beg you to eat it. As Wendell Berry put it, "If they could figure out a profitable way to prechew and force feed it they'd do that too."*
Further, if commerce had things their way, society would be enclosed within walls containing only one-way valves where their food gadgets come in but no thinking can come out. Better yet, we and our pets should be strapped to the dinner table with stomach tubes coming direct from the factory and money conveyors going back. Actually, the AAFCO ingredient list has closed the loop even more completely with approval of feces and garbage as food. Tubes could run to "eat" and "exit" ends in a nice tidy closed circuit direct to and from industrialists.
As much as supplemental independent grocery store feeding is cautioned against, there must surely be some evidence of damage from this feeding practice. But other than occasional reports of problems brought on by feeding large quantities of cooked bones, or meat only, or liver only, or fish in excess, there is no such evidence. In 17 years of medical practice I did not see one such problem.
Of course, ridiculous excesses of anything can cause problems. Even oxygen and water can kill if overdosed. But feeding fresh foods, in variety, can cause only health - not disease. If you believe that the natural instincts of your companion animal mean anything, offer some clean, raw liver or meat and observe. Case closed.
* Wysong Health Letter, "Don't Let Apparently Youthful Health Fool You," 7(12):6. J Am Coll Cardiol, 1993; 22(2): 459-67. J Am Med Assoc, 1999: 281:727-35.