Vets slam grain-free food as not ‘necessarily’ superior

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, and yet many pets are overweight or obese.

The unpleasant prospect of the simple solution – feeding our furry friends less – makes owners reach for alternative, quick-fix strategies. Some pet parents have turned to radically new menus. These grain-free, all-meat and rawfood diets are inspired by the meals eaten by wild relatives of our Fidos and Felixes.

But are these diets really better? Veterinarians and pet nutrition researchers say probably not.

According to clinical veterinary nutritionists at Tufts University, grain-free foods were one of the fastestgrowing sectors of the pet food market in 2016. “All I ever hear is, oh, on a good diet, it’s grainfree,” said veterinarian Dena Lock.

“It’s a marketing trend,” Lock said.

“Grain-free is marketing. It’s only marketing,” said Cailin Heinze, a smallanimal nutritionist at Tufts University’s 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,” said Jennifer Larsen, a clinical nutritionist at the University of California Veterinary School in Davis. People think 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 is no data to support the assertion that grain-free diets are better for pets, Heinze and Larsen noted. “It’s much more common for dogs to have allergies to meat than to grain,” Heinz said. 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.

Some US marketing campaigns claim grain-free, meat-forward formulations reflect the ancestral diets of our dogs’ and cats’ evolutionary predecessors, but veterinarians questioned this logic.

“People believe that nature is best,” Larsen said, but “animals in the wild don’t live that long and they don’t lead very healthy lives.”

Dogs diverged from wolves genetically in their ability to digest starches. “Dogs aren’t wolves,” said Robert Wayne, a canine geneticist at UCLA. “They have adapted to a human diet.”

Research in Wayne’s lab showed most wolves carry two copies of a gene involved in starch digestion, while dogs have between three and 29 copies. According to Heinze, the average dog can easily handle 50% of its diet as carbs.

Cats are carnivores rather than omnivores, so they have higher protein requirements than dogs, but “cats can digest and utilise carbohydrates quite well”, said Andrea Fascetti, a veterinary nutritionist at the University of California Veterinary School.

Many grain-free pet foods are made with starch from potatoes or lentils and may be higher in fat. If you cut grains but increase calories, your pet is going to gain weight, Heinze said.

Dogs and cats also have a drastically different lifestyle from wolves or tigers. Pets are usually spayed and neutered, which is a risk factor for obesity. And as most live inside or in enclosed spaces, energy needs are reduced dramatically.

In the wild, wolves and feline predators eat the hair, bones and cartilage of their prey, not just meat. Pet owners who do choose to feed their animals an all-meat diet, must add supplements to make sure their pet isn’t missing out on key nutrients such as calcium, Fascetti said. Experts especially caution against feeding pets raw meat.

“It’s not uncommon to find things like salmonella and E coli and listeria in raw meat,” Larsen said. There are a lot of microbes present in our farming systems, and unlike when an animal is hunting in the wild, there are many opportunities for bacteria to contaminate meat between the time an animal is slaughtered and when it reaches kitchens.

But what about all those benefits you hear about from feeding a raw diet, like shiny coats and less frequent stools?

Raw diets tend to be lower in fibre, and high fibre probably results in larger stools. But we don’t have a sense of whether stool quality and quantity correlate with health, Fascetti said. And that shiny coat probably is because of high fat.

If pet owners wish to formulate their own diets, they should work with their veterinarian and a certified nutritionist. If you’re feeding your pet a balanced diet such as in a commercial chow, obesity is the biggest nutrition issue pet owners should worry about.

There’s no one magic diet for every animal. Experts recommend working with your veterinarian to find a diet that works for you and your pet.

In the pet food aisle, try not to get too hung up on “the no list”, Heinze said. “Claims like no gluten, no grains and no soy generally mean no science.” – Washington Post