The 33-year-old TOWIE star admitted he is currently 27 stone and is awaiting gastric surgery to help him lose weight, as he has a family history of heart problems and fears his life is at risk.
Argent told Good Morning Britain: "I’ve been speaking regularly to the doctors and nurses... They’ve basically been saying, the size I am at the moment, it could be fatal.
"If I was to catch COVID, I could be a goner. It’s not just that, my mum and dad, they’ve had heart problems themselves, so it’s kind of in my family hereditary, in my genes and stuff.
"I’ve got to tackle this now before it’s too late.”
The reality TV star - who suffers from asthma, as well as being medically obese - received his first dose of the coronavirus vaccine last month.
Watch: What is long COVID?
Argent confirmed he is booked in to undergo weight-loss surgery, although he has not decided exactly which procedure will be right for him.
He said: “It’s not like I’ve put weight on in lockdown and I’m doing something drastic to get it off. This is something that I’ve had this underlying issue in terms of weight and eating disorder since I was a teenager.
“It’s a really, really serious operation. At the moment I haven’t decided specifically which one it’s going to be, there’s options of a sleeve, bypass, I need to still do a bit more research.
"But the surgery is going to happen, it’s going to happen in the near future. I really hope it’s going to work for me, it’s going to be life changing.”
Argent also revealed that he and on-off girlfriend Gemma Collins, 40, have rekindled their friendship following a difficult break-up last year.
He said: “We’re not officially back together. It’s impossible to be in a relationship with anyone bearing in mind I can’t meet anyone outside of my house and stuff like that. But I suppose on the positive note, she’s no longer blocked on my phone.
"We’re friends at the moment and we have been in contact and you know, whatever happens between me and Gemma, we’ve been through a hell of a lot together and we’re always going to be close.”
And asked about Collins' claims she made up her sex tape Argent said: "If she had made a sex tape it certainly wasn’t with me."
The former The Only Way Is Essex stars have been in an on-off relationship since 2012.
Last year Argent revealed he had entered rehab for cocaine addiction following a near-fatal cocaine overdose in 2019.
Speaking about Collins at the time he said she was “not an enabler”, and had been “extremely tough” on him over his drugs use.
Watch: James Argent give credit to Gemma Collins for how she handled his drug addiction