A fat cat named Cinderblock on an aspirational mission to slim down has become a darling of the internet, but felines everywhere should likely be joining her in the battle against the bulge.

"Yes, cats are getting fatter," said Kären Marsden, owner of Edmonton Holistic Veterinary Clinic. "They are, unfortunately. They're very, very well fed.

"We body score cats, like a one to 10. And most of the cats I see are up at an eight, for sure. We call it shrinking-head syndrome."

Cinderblock, a portly creature initially clocking in at 25 pounds, is on a very public weight-loss journey.

The Washington State cat was relinquished to a veterinary hospital, due to poor mobility. According to the vet, her morbid obesity was affecting her quality of life.

The clinic has been documenting Cinderblock's weight loss journey through prescription diet and exercise in a series of social media posts.

A video of her meowing disgruntledly while using a treadmill with one lackadaisical paw has been viewed millions of times.

But this trend isn't just internet nonsense. House cats really are getting fatter.

'Addicted to kibble'

"I feel sorry for the cat," Marsden said in an interview with CBC Radio's Edmonton AM.

"Obviously it's not good for the cat. It's probably been fed a lot. You know, cats will keep eating and then they get kind of addicted to kibble."

"Losing weight is a slow process in cats. It's hard, people feel guilty."

A study involving more than 19 million cats from across Canada and the United States suggests most of the animals continue to put on weight after they reach adulthood and their heaviest weight is higher than it was two decades ago.

Researchers at the Ontario Veterinary College at the University of Guelph analyzed 54 million weight measurements taken at vet offices between 1981 and mid-2016 to get a sense of the typical weight gain and loss pattern over the course of a cat's life.

The study was published in the Journal of the American Veterinary Medical Association earlier this year. Marsden said the trend is concerning. Obesity can cause a slate of health problems, including diabetes and fatty liver syndrome.

They can literally be on cat-kins, like the Atkins diet for cats. - Kären Marsden

Feeding your cat the wrong kind of kibble is often to blame, Marsden said. Many brands contain hidden carbohydrates like grain or corn.

Just like humans, cutting out the carbs can help slim things down.

"If they're overweight, they don't need peas or potatoes," Marsden said.

"We have carnivores being fed like they're omnivores. They are designed to have a protein-rich meal a couple of times a day, not the grazing, not the convenience.

"They can literally be on cat-kins, like the Atkins diet for cats."

'Meow, meow, meow'

Marsden said cats are also less active than they used to be. As more cats spend time indoors, they also tend to become more sedentary and put on weight.

And then there is the problem of weak-willed owners succumbing too often to the hunger cries of their cats.

Even Marsden's husband, also a veterinarian, has fallen victim to these feline tactics.

"Our cats, as soon as they see him, they're all, 'meow, meow, meow,' because they know he can't take the heat.

"They are very dramatic. They have him trained."

Marsden recommends owners spend more time playing with their cats and distract them from their false hunger pains with toys and catnip.

"The holidays are coming and it's probably time to look at your slightly chubby kitty and get him some toys.

"Get them a laser pointer or even catnip. Even older cats will be intrigued, it just distracts them.

"It's sort of like giving your cat an iPhone."