Man has suspected heart attack while eating 6,000-calorie burger at Heart Attack Grill in Las Vegas (VIDEO)

A man reportedly suffered a heart attack while eating the "Triple Bypass Burger" at the Heart Attack Grill, a Las Vegas restaurant that serves free meals to people who weigh over 350 pounds.

The man, in his 40s, was reportedly dining alone and eating the 6,000-calorie burger on Saturday when he started sweating, shaking and could barely talk, owner Jon Basso said.

"It was no joke," Basso, who calls himself "Doctor Jon" although he admits he does not have a medical degree recognized by the American Medical Association, told Fox5 News.

Basso said he immediately called 911.

"Tourists were taking photos of him as if it were some type of stunt," Basso said. "Even with our own morbid sense of humor, we would never pull a stunt like that."

When Basso himself expresses doubt the man was really having a heart attack, one of his employees said,  "No, he’s really having an f-ing heart attack," ABC News reported.

The man was taken to hospital by paramedics, but his condition was not disclosed, the Associated Press reported.

Meanwhile, as restaurants around the US reportedly pare down their portions and offer healthy choices, the Heart Attack Grill, which opened in October in downtown Las Vegas, has made a name for itself serving high-calorie, high-fat foods in limitless portions. 

The restaurant's motto is "A taste worth dying for," while gimmicks include an all-you-can-eat "Flatliner" fry bar, scantily-clad "nurses" as waitresses, referring to customers as patients.

According to Medical Daily, the restaurant has a sign that says that says: "Caution! This establishment is bad for your health."

Basso said there had been a "variety of incidents" at the restaurant, but Saturday was the first time there was a full-scale coronary.  

USA Today reported that just last March, the restaurant’s spokesperson Blair River — who weighed 575 pounds — died at 29 years old from pneumonia.

An amateur video posted on YouTube shows the unidentified man being wheeled out of the Heart Attack Grill on a stretcher after the incident. 

Here's the Man v Food take:

And a little tongue in cheek "humor" from the restaurant's founder: