Losing weight is tough. It would be easier if a benevolent someone concerned about your health controlled exactly how much you ate and how often you exercised, right? That's the situation for most dogs and cats in the United States, and yet the majority are overweight or obese.
As with our own dieting woes, the unpleasant prospect of the simple solution -- feeding our furry friends less -- makes us reach for alternate, quick-fix strategies. Many pet owners have turned to radically new menus. These grain-free, all-meat and raw-food diets are inspired by the meals eaten by wild relatives of our dogs and cats.
But are these diets really better for our pets? Veterinarians and pet nutrition researchers say probably not.
According to clinical veterinary nutritionists at Tufts University, grain-free foods were one of the fastest-growing sectors of the pet food market in 2016. "All I ever hear is, oh, on a good diet, it's grain free," says Dena Lock, a veterinarian in Texas. The majority of her pet patients are overweight.
Why have these pet diets become so popular?
"It's a marketing trend," Lock says.
"Grain-free is marketing. It's only marketing," says Cailin Heinze, a small-animal nutritionist at Tufts University's Cummings School of Veterinary Medicine. "A lot of foods market themselves by what they're not including," and the implication is that the excluded ingredient must be bad.
"Grain-free is definitely a marketing technique that has been very successful," says Jennifer Larsen, a clinical nutritionist at the University of California Veterinary School in Davis. People think that if they pay a lot for food and there are a lot of exclusions on the bag, that the food is healthier, but "they're buying an idea," she said, "not necessarily a superior product."
There are no data to support the idea that grain-free diets are better for pets, Heinze and Larsen note.
Some pet owners have a false impression that grains are more likely to cause an allergic reaction, but "it's much more common for dogs to have allergies to meat than to grain," Heinz says. Chicken, beef, eggs, dairy and wheat are the most common allergies in dogs. And it's not that there's anything particularly allergenic about these foods, she said, they're just the most frequently used ingredients.
Marketing campaigns such as Blue Buffalo's "Wilderness" or Chewy's "Taste of Wild" claim that their grain-free, meat-forward formulations better reflect the ancestral diets of our dogs' and cats' evolutionary predecessors, but veterinarians question this logic.
For one, our pets' wild cousins aren't all that healthy. "People believe that nature is best," Larsen says, but "animals in the wild don't live that long and they don't lead very healthy lives."
For dogs, we know that they have diverged from wolves genetically in their ability to digest starches. "Dogs aren't wolves," says Robert Wayne, a canine geneticist at UCLA. "They have adapted to a human diet." Research in Wayne's lab showed that most wolves carry two copies of a gene involved in starch digestion, while dogs have between 3 and 29 copies. According to Heinze, the average dog can easily handle 50 percent of its diet as carbs.
For cats, this argument makes a little more sense. Cats are carnivores rather than omnivores, so they have higher protein requirements than dogs, but "cats can digest and utilize carbohydrates quite well," says Andrea Fascetti, a veterinary nutritionist at UCD Veterinary School.
Many grain-free pet foods are made with starch from potatoes or lentils and can be higher in fat. If you cut grains but increase calories, your pet is going to gain weight, Heinze says.
Style on 08/22/2017