The mother of two children, aged three and 14, models on a website, where admirers and the curious can pay to watch videos of her eating greasy foods or walking to the car.
She has appeared in television interviews and said she welcomes media coverage.
A Guinness World Records spokesman said Miss Simpson has submitted a claim for the title of world's heaviest woman to give birth, a claim that is being reviewed.
Among the heaviest women ever recorded was one who reportedly weighed 128st and another who reportedly weighed 85st at the time of their deaths.
Miss Simpson said she has received a book offer and wants her own reality show, partly to give plus-size women more confidence. She wears size XXXXXL clothing, which she buys mostly online, and calls herself a member of the "fat acceptance community."
"The bigger your butt is, the bigger belly you have, the sexier you are," she said.
Miss Simpson has found a man who says he appreciates her size, and they plan to marry in Hawaii this year. She said airlines are being accommodating of her needs.
Her fiancée, 49-year-old Philippe Gouamba and the father of her three-year-old daughter, said he not only finds her attractive but is also one of her biggest supporters in her quest to expand her girth.
"You look at her curves and see her full belly and generous hips," Mr Gouamba said. "It's very sexy."
Miss Simpson said she gets emails from women who think they will never fall in love or have children because of their weight.
"I just say that's not true," Simpson said. "I would love to be a voice, so that people can see a woman of size having a regular family."
Miss Simpson spends as much as £516 a week on groceries, suffers from Type 2 diabetes and struggles with basic tasks such as cooking and taking a shower.
But she dismisses critics who warn that her weight can lead to heart problems, aggravate her diabetes and cause pressure on her joints.
"I'm very healthy. I go to the doctor every three months," she said.
A Guinness World Records spokesman said Miss Simpson has submitted a claim for the title of world's heaviest woman to give birth, a claim that is being reviewed.
Miss Simpson said she has received a book offer and wants her own reality show, partly to give plus-size women more confidence. She wears size XXXXXL clothing, which she buys mostly online, and calls herself a member of the "fat acceptance community."
"The bigger your butt is, the bigger belly you have, the sexier you are," she said.
Miss Simpson has found a man who says he appreciates her size, and they plan to marry in Hawaii this year. She said airlines are being accommodating of her needs.
Her fiancée, 49-year-old Philippe Gouamba and the father of her three-year-old daughter, said he not only finds her attractive but is also one of her biggest supporters in her quest to expand her girth.
Miss Simpson said she gets emails from women who think they will never fall in love or have children because of their weight.
"I just say that's not true," Simpson said. "I would love to be a voice, so that people can see a woman of size having a regular family."
Miss Simpson spends as much as £516 a week on groceries, suffers from Type 2 diabetes and struggles with basic tasks such as cooking and taking a shower.
But she dismisses critics who warn that her weight can lead to heart problems, aggravate her diabetes and cause pressure on her joints.
"I'm very healthy. I go to the doctor every three months," she said.