The 27-year-old, who won the reality show in 2015 and who gave birth to a son last summer, has admitted that she piled on five stones during her pregnancy and took to social media to make a moving confession to her 50,000 followers on how her weight had reduced her to tears.
On Twitter, she wrote: "Had a little cry writing this. This is no black toothpaste, diet pill bulls***.
"This is me just putting pressure on myself to do this by putting it out there."
She wrote: "I am morbidly obese. I gained five stone during my pregnancy - my midwife said if they gave out awards for weight gain I'd of won.
"I literally cry in changing rooms when I have to tuck my belly into size 16 jeans and even then I have to literally squeeze the button into the hole."
Chloe, who gave birth to son Vinnie John last summer, pocketed the £116,000 prize on the reality show three years ago - but shunned the celebrity lifestyle to return to her job working in a call centre.
She added: "I've had strangers stop me and literally say 'wow, you've put so much weight on. I'm ashamed of myself for letting it happen.
"So this is it. Today's the biggest I'll ever be.
"I'm purely writing this so that I have no going back because I'll look a fool if I quit. I'll never be skinny but I'd just like to be slightly chubby and cute rather than morbidly obese - so there it is.
"I'm fat and I'm unhappy BUT I'm doing something about it and I can't wait to show you all my before and after pictures."
She added that she was following the diet plan devised by Doncaster weight loss guru Terri Ann Nunns, who rakes in £500,000 a year after creating her own weight loss plan from the elements of different diets that worked for her and turning it into her own business.