Dog Food and Canine Nutrition with Marion Nestle and Malden Nesheim

By Claudia Kawczynska, November 2008, Updated June 2021

Marion Nestle, PhD, MPH, is the Paulette Goddard professor of nutrition, food studies and public health at New York University. Her latest book, What to Eat, inspired her work in progress, What Pets Eat. She and her partner, Malden Nesheim, PhD, professor and provost emeritus of Cornell University, are currently conducting research for this book. We’re pleased to announce that both have agreed to serve as Bark’s nutrition editors, and we begin with an introductory Q&A.

Bark: In What to Eat, you set out to tell us how to make sensible food choices for ourselves; in your new project, What Pets Eat, are you hoping to do the same for our pets? Could you say more about what you mean by “sensible food”?

Nestle & Nesheim: Happy to. What to Eat evolved in response to complaints that people were totally confused about how to make food choices. We see the pet food marketplace as just as daunting—so many products, so many health promises and so much contradictory information. We think we can bring some common sense and clarity to the discussion and base what we say on real research. Plenty of studies provide useful information about what pets need to eat. Just as with human diets, there are many different ways to meet nutritional needs. Every one of them—commercial food, home-made food, table food, dry food, wet food, raw food—can work well if done properly, and “properly” isn’t all that hard to do.

B: What are the similarities between dog and human nutrition? While it is said that dogs have metabolisms similar to ours, there are those who believe that dogs are carnivores, while humans are omnivores—doesn’t this affect food requirements for our two species?

N&N: It’s no surprise that dogs and humans have quite similar food needs. We both need the same nutrients to support growth and health, and our digestive systems work to process food in much the same way. This similarity is undoubtedly one of the reasons dogs and humans have gotten along so well for thousands of years. Modern dogs have evolved to be more omnivorous and do well on the foods we typically consume—the healthier foods, of course. Just because dogs can eat junk foods doesn’t mean they should.


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B: How closely aligned are the human food and pet food industries? Is the level of control and oversight the same?

N&N: The best-known pet food brands pretty much all belong to big-time companies that make foods or other products for humans. Nestlé (no relation, by the way), Mars, Colgate, Procter & Gamble, Del Monte and Wal-Mart dominate pet food sales in the United States. But the systems for regulating human and pet food differ in some ways. The FDA regulates human foods through its Center for Food Safety and Applied Nutrition, but it regulates pet foods through its Center for Veterinary Medicine. This means that pet foods are covered by the rules that govern food for farm animals, not people. States have their own regulations for feed control and these also apply to pet foods. The Federal Food, Drug, and Cosmetic Act applies to both human and pet foods, but not in the same way. Labels are one obvious place where the rules for human and pet foods differ.

Historically, the states have been more involved in the enforcement of animal feed regulations than has the FDA, except in the area of feed additives. But Congress has just tucked legislation about pet foods into the Prescription Drug User Fee Act, signed into law in September. This requires AAFCO—the Association of American Feed Control Officials—and the pet food industry to set processing and ingredient standards for pet food labels and to develop a system for identifying and monitoring illnesses associated with the foods. Let’s hope they do this, and soon.

B: How are the two industries linked? It is said that pet food is actually made from the “scraps” left over from the production of human food; do you see it this way?

N&N: That is certainly one way to look at it. The National Renderers Association estimates that 25 percent of rendered products left over from processing cattle, pigs and chickens for human food goes into pet foods in the form of meat- and bone meal or poultry by-product meal. Brewers rice is composed of broken and cracked rice grains that are not sold on the human market. Soybean meal is what is left after soy (“vegetable”) oil is extracted from soybeans. The animal feed industry—including the pet food industry—uses the materials that remain after production of many human foods, among them sugar, alcohol, beer, and flour as well as cattle, pigs and chickens. Many of these materials contribute nutrients—vitamins, minerals, protein—or energy that dogs can use.

B: In your writing, you warn against a “nutrient-by-nutrient approach to food” because it “takes the nutrient out of the context of the food.” What do you mean by that?

N&N: Whenever we see advertisements for specific vitamins, we know that marketing departments must be hard at work. Dogs, like humans, require more than 40 separate nutrients to grow, reproduce and stay healthy. They, like us, need every one of them. No pill can provide them all, so it’s best to get them from food. Most foods contain a great many nutrients, but in different proportions. So the best way to get all the nutrients is to mix and match food intake—eat a variety of foods from different groups (as we were taught in the third grade). Commercial dog food takes care of having to worry about the mixing and matching by putting a bunch of different ingredients in one can or pellet. But the nutrition principles are the same.

B: What do you see as the biggest trend in nutrition and eating?

N&N: We see two trends: one good, one not so good. The good one is heading toward better quality products—natural, organic, whole, unprocessed and locally grown. The not-so-good one is heading toward eating more food, more often, in more places, and taking in far more calories than are used up in activity. It’s pretty obvious that both trends apply to dogs as well as people.

B: The “Slow Food” movement and other eating-local movements seem, to some, to apply only to the upper echelon of consumers—do you think it is possible to feed all consumers and their pets good, fresh, nutritious foods without using industrial food products? Does food have to be mass-produced and/or processed to be affordable? Convenience and affordability—what other factors dictate food choices?

N&N: You’ve asked lots of questions here. Let’s start with the one about elitism. We view what’s happening with food these days as coming close to being a social movement based on classic democratic principles—of the people, by the people, for the people. Social movements have to start somewhere and some of the most important ones—women’s suffrage, civil rights and environmentalism leap to mind—started with the elite. Today, organics are the fastest-growing segment of the food industry. The laws of supply and demand suggest that as the supply of organics increases, prices will fall. This is already happening.

The issues of mass production and affordability are complicated and depend on federal farm policies, among other arcane matters. Those who grow corn get billions in federal subsidies, and corn was really cheap until we started growing it for fuel. That’s why corn appears as an ingredient in so many pet foods. That’s also why so many people want farm policy changed. The Farm Bill [known in Congress as the Farm, Nutrition, and Bioenergy Act of 2007] was up for renewal in 2007. At the time of this writing, it did not look as though Congress would be brave enough to make significant changes in it, so advocates are already gearing up for the next round in 2012.

As for what dictates food choice: Price and convenience matter a lot, but so does perception. That’s where advertising comes in. We will have a lot to say in our book about the way pet foods are marketed. For human foods, environmental factors—portion size, proximity and peer pressure, for example—strongly influence caloric intake. But as a pet owner, you have complete control over your dog’s food environment.

B: When you take into consideration the number of companion animals in this country, do you think that commercial diets are the most pragmatic way to meet their feeding needs? Is a pet food revolution underway?

N&N: We think pets can be fed very well on diets prepared at home if owners provide a variety of healthful foods that include the needed nutrients (a multivitamin supplement is also a good idea). The “if” in that statement requires some knowledge and thought. Commercial pet foods are popular for precisely the same reason convenience foods and fast foods are popular: You don’t need to spend much time, effort or thought to open a can or a bag of dog food. We see a growing movement of pet owners who want to be more involved with their dog’s diet, just as there is a growing movement of consumers who want to know more about what’s in their food and where it comes from. We think both trends are great.

B: In many of your books, you take on the food industry—a huge business in this country. What impact do you think industry lobbyists have in setting U.S. nutrition policy? Are you seeing a similar impact on the pet food industry and the way its “standards” are set? As for regulatory standards, how similar are they in the two food sectors?

N&N: As Food Politics describes, every food company has its own lobbyist or trade association to protect its interests and make sure no government agency imposes regulations that might encourage people to eat less of its products. But the human food industry is a trillion dollar a year business (half spent on food prepared or served outside the home). Pet food’s $15 billion or so is dog biscuits in comparison to revenues from human foods sold by companies like Nestlé or Wal-Mart. As we learned from the Menu Foods recall, the regulatory standards in the two sectors are similar in some ways. One of them is crucial: The FDA can’t order recalls. It can only politely request voluntary recalls. We suspect food lobbyists like it that way.

B: What have you learned about AAFCO and how nutrition standards are established for companion animals?

N&N: AAFCO describes itself as a nonprofit group of officials or employees of state or federal agencies charged with regulating animal feed. It operates through committees that work on such matters as labeling, ingredient definitions, model feed laws and enforcement. A committee recommends standards for pet foods, usually by appointing an expert group made up of government, academic and industry representatives. Currently, AAFCO is reexamining its standards in light of the recent National Research Council report, “Nutritional Requirements of Dogs and Cats.” AAFCO committees also work closely with advisory groups that consist of representatives from industry groups. The industry participates in AAFCO deliberations but does not have a vote.

B: You have remarked that the pet food and human food sectors are remarkably similar in the way the foods are marketed (claims for health, disease prevention and aging), but there is much less transparency in composition and ingredients in the pet food industry. Have you been able to actually understand and deconstruct the ingredients by simply reading a pet food label?

N&N: Yes, with a little help from some great books on food ingredients. Pet food labels are supposed to display the name of the food, the manufacturer, what the product is for, how its nutritional adequacy has been determined, feeding directions and the list of ingredients in descending order of amount in the food. The ingredient present in the greatest amount comes first. The labels also are supposed to give the guaranteed analysis for moisture, crude protein, fat and fiber. The ingredient list is usually very long, but only the first few ingredients—maybe just the first five or six—really matter. The rest are unpronounceable flavor and texture additives, vitamins, and minerals that go on and on and make the list seem daunting.

Some of these additives do not contribute nutrients but are there to make the products taste better (flavor additives, “digest”), stick together (montmorillonite, bentonite), keep the fat from running (beet pulp, tomato pomace) and appear more acceptable to owners (caramel color). The infamous recalled “wheat gluten” (which was really melamine-laced wheat flour) was supposed to be there to thicken gravy but also to contribute protein. Additives all have a purpose in commercial dog food formulas. They are all approved by the FDA or are considered “Generally Recognized As Safe” (GRAS). Whether they constitute “junk” depends on point of view. Our preference is to reserve the term “junk” for pet treats that provide calories but are not required to meet nutritional standards.

B: As has been evidenced by the public response to the latest food recall, pet lovers are increasingly aware that they must know more about the food they feed their companion animals. Are you interested in hearing from our readers with questions they might have as you investigate the pet food industry?

N&N: Yes! We would love to hear from readers about what they want to know. We will make certain we get those questions answered in our book, if not sooner.

B: Many of us would also like to better understand the link between the industry and the role that veterinarians play in directing our pets’ dietary regimes. What kind of information can our readers provide you to help in that phase of your work?

N&N: We know enough about medical education to know that doctors know hardly anything about nutrition. The same is true of veterinarians. Most veterinary colleges teach nutrition only minimally, meaning that veterinarians get their nutrition information from pet food companies. We would love to hear from veterinarians about the nutrition problems they encounter in their practices and the ways in which pet food companies transmit information about how to treat these problems. We would love to hear from pet owners about what veterinarians tell them about dog feeding, which commercial products they recommend, whether they sell foods in their offices and what kind of nutrition education they provide. We are delighted to have this forum and would like to make it as useful as possible for Bark readers.

Marion Nestle can be contacted at and Malden Nesheim, at Their most recent book, Pet Food Politics, is now available from the University of California Press.


Claudia Kawczynska is The Bark's co-founder and Editor-in-Chief.

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