The 42-year-old from New Jersey is set on reaching the 1,000lb mark (71st) in just two years.
Remarkably, she insists she is healthy despite now needing a mobility scooter when she goes shopping.
“My favourite food is sushi, but unlike others I can sit and eat 70 big pieces of sushi in one go,” the American told the Daily Mail.
"I have to eat 12,000 calories a day and hope to achieve my goal in two years." Donna, who wears XXXXXXXL dresses, eats mounds of junk food and tries to move as little as possible.
Ms Simpson already holds the Guinness World Record as the world's fattest mother.
Simpson says her boyfriend Philippe, who she reportedly met in a fat fetish chat room, encourages her.
“I think he’d like it if I was bigger. He’s a real belly man.”
Simpson makes money by running a website where men pay to watch her eating food.
"I love eating, and people love watching me eat. It makes people happy, and I’m not harming anyone.”
Donna Simpson - World's Fattest Lady