A cat owner had no idea why the wall near the door was always dirty, until she caught the culprit on camera and publicly shamed him on social media.

In a viral TikTok video shared on Thursday by @itsjaxdex, the poster's cat, Gary, who is currently on a diet, can be seen struggling to get in through the flap because of his size, tapping his paws on the side of the wall to help himself move forward.

"Now I know why I keep having to clean the wall," reads layover text in the clip. And a caption continues: "Fat cat." Newsweek reached out to @itsjaxdex for comment. We could not verify the details of the case.

An article written by veterinarians from VCA Animal Hospitals says that, in the United States, obesity is the most common preventable disease among cats, and almost 60 percent of them are overweight.

Because every cat is different, there is no standard weight that can be taken as a guideline. However, a feline's best weight is generally the same amount they weighed when they first entered adulthood.

Our pets are usually considered overweight when they are around 10 percent above their ideal weight. They become obese when they weigh over 20 percent more than their ideal weight.

While chubby cats may look cute, obesity can shorten their life and expose them to elevated risks of cancer, diabetes mellitus, heart disease and hypertension, osteoarthritis and faster degeneration of affected joints, urinary bladder stones, and anesthetic complications.

That's why you should always check your cat's weight and help them lose excess fat should they need to.

A Catster article by Dr. Joanna Woodnutt says that, before putting your cat on a diet, you should always consult a veterinarian, so they can give you guidelines to help them lose weight safely.

With a healthy diet, cats can lose up to 0.5 to 1 percent of body weight per week, although some felines may take some weeks before starting to see any results. Exceeding this amount can cause serious issues such as fatty liver disease.

You can still feed your cat treats while they are on a diet; just stick to low-calorie ones, and ensure they don't make up more than 10 percent of their total daily calorie allowance.

The video quickly went viral on social media and has so far received over 5.9 million views and almost 1 million likes on the platform.

One user, Kris, commented: "He's eating multiple dinners in diff [different] homes."

Shine_on_crzy_diamond posted: "He said that door gets smaller every freaking day."

Nova added: "I love the look at the camera as if to say 'what? You got a problem?"

Do you have funny and adorable videos or pictures of your pet you want to share? Send them to life@newsweek.com with some details about your best friend, and they could appear in our Pet of the Week lineup.