Donna Simpson, 42, already weighs 600 pounds. She hopes to add another 400 to her frame within two years.
To do it, she's eating 12,000 calories a day and trying to move as little as possible.
It's a costly endeavor: Simpson estimates that she spends $750 a week on groceries, which is financed by her Web site, where fans can watch streaming video of Simpson as she eats.
The idea was inspired by her boyfriend, Philippe, whom Simpson describes as "a real belly lover" and an enthusiastic supporter of her weight gain goal.
"I think he'd like it if I was bigger," Simpson told the U.K.'s Daily Mail. She met Philippe in a fat fetish chat room in 2006.
In 2007, Simpson became the fattest woman ever to give birth when she delivered daughter Jacqueline with the help of 30 doctors, nurses and medical assistants.
Despite the high-risk childbirth, a diagnosis of diabetes and her reliance on a motorized scooter for errands that require more than 20 feet of walking, Simpson describes herself as healthy -- and happy.
"I love eating, and people love watching me eat," she said. "It makes people happy, and I'm not harming anyone."
Simpson is rapidly progressing toward membership in a very small group. "The 900 Club," as dubbed by Dimensions magazine, consists of those who do, or did, exceed the 900-pound mark. And if the company she keeps is any indication, Simpson might not live long enough to become a 1,000-pound woman.
Even if Simpson attains her goal, she'll still be 600 pounds shy of Carol Yager, once the world's fattest woman, who died at 33 in 1994. Yager, who refused hospitalization because she didn't think her health problems were critical, succumbed to kidney failure and severe water retention.
It took 13 people to roll John Brower Minnoch over in bed. At 1,400 pounds in 1979, he claimed his health suffered only after a 500 calories a day diet left him sapped of energy. Minnoch died at 42 after lapsing from a medically supervised diet and regaining 200 pounds in a single week, which led to fatal edema.
Formerly the world's fattest woman, Rosalie Bradford also set a record, for most weight lost by a woman, after shedding more than 900 pounds with the help of diet guru Richard Simmons. Despite her success, Bradford died in 2006 of undisclosed health problems.
Ironically, it was the 2007 death of Renee Williams, a 29-year-old Texan, that prompted Simpson to refuse weight loss surgery. Williams, who weighed 850 pounds when she died, was desperate to lose weight from surgery but was considered "high risk" by most doctors. She suffered a heart attack during gastric bypass surgery.
Of all those whose weight puts them within Simpson's professed target on the scale, none have lived to enjoy old age.
Even the world's former fattest man, Manuel Uribe, has changed his tune. After years of refusing weight loss surgery, Uribe has lost more than 600 pounds on the Zone Diet and recently married his girlfriend on a beach in Mexico -- from bed.
Despite the massive weight loss, Uribe's health problems still prevent him from walking.
Simpson may be making headlines for her weight gain ambition, but she doesn't actually have much competition -- they've all died off. The last known woman to exceed 1,000 pounds was Renee Scarfa, who died of weight-related heart problems in 2008, at age 42.