Today’s New York Times featured Dr. Tony Buffington, of The Ohio State University, answering questions about pet food. (Click here to read the full article in the NYT.) For fun, I thought I’d take a shot at answering the same questions, so you can compare and contrast!

Q. I buy grain-free food for my 5-year-old Labrador retriever mostly to avoid foods with fillers and/or unreliable ingredients. Your thoughts on such a diet? Also, is dog food irradiated in the United States? – JK, Flemington, N.J.

I have an issue with “grain-free” pet foods, or at least with their advertising, because most “grain-free” foods simply substitute starchy vegetables for grains, which is not an improvement. The grain that ends up in pet food may contain mold or excessive pesticide residues, so it makes sense to look for alternatives, but white potatoes and green peas (the most common substitutes) are even higher on the glycemic index than grain–a serious issue for cats, who are susceptible to diabetes from the wild insulin swings these foods cause). The grain that truly should be avoided is corn, since it is high in sugar, and the majority of corn grown in the U.S. is genetically modified. It’s better for both dogs and cats to be fed low-carbohydrate food, but very few grain-free foods fit that description.

On irradiation, current U.S. law mandates that all irradiated food must be labeled with the radura symbol. My concern is: who knows how well manufacturers comply with the rules?

Q. What do you think of this easy check? If the can or box includes corn gluten or animal byproducts (this means dying/diseased animals), don’t buy it. – SKV

These two rules will quickly disqualify most cheap foods, giving you more time to study more appropriate candidates. Corn gluten is a cheap substitute for animal protein; its presence is a red flag for junky ingredients. By-products in and of themselves aren’t bad; but are undesirable when they are used as substitutes for real meat, which is more expensive. I would also add “meat-and-bone-meal” and “animal fat” as disqualifiers. For more complete “rules” see my article on Selecting a Good Commercial Pet Food.

Q. My Italian friends just feed their dog whatever they have cooked for dinner. It’s much simpler. – Stacy, London

Fine with me! As long as the humans are eating a relatively healthy, balanced diet, it’s no problem to share it with your dogs. Dogs survived–and thrived–this way for many millennia before commercial pet food was invented. Now, if you’re the sort that lives on popcorn, Cheetos, and beer…maybe not so much!  (Dogs and humans have very similar nutritional requirements, but cats have specific nutritional needs that may require additional supplementation.)

Q. This all presumes that what is good for humans is good for their pets, and that pets’ tastes are the same as humans’. The goal should be to find out what is good for and pleasing to the animals, not offering free samples to their owners. What kind of dog wants to eat blueberries? – foo, Washington, D.C.

Among canids, foxes and coyotes actually eat a lot of berries (and other fruit) when available. But for dogs and cats, it’s the humans that buy the food. Pet food marketing is therefore aimed at human eyes and human tastes. What’s good for pets and what appeals to guardians may be quite different; but at least there are rudimentary standards for pet food that ensure a basic level of nutrition. It definitely isn’t a good idea to rely on your pet’s taste in picking food, because pet food manufacturers are experts in making even the worst ingredients taste good. Gosh, if I ate according to what I like, I would spend my life commuting between Taco Bell and Dairy Queen. Someone has to be the grownup! My cats get what I want them to eat, and if they don’t like it…too bad! They’ve learned to eat what I give them. I don’t care whether they’re enthusiastic about it or not, because I’m a better judge of what’s good for them than they are. It’s up to pet parents to educate themselves about nutrition and make those tough choices based on that that knowledge!