Donna Simpson, from New Jersey, weighs 273kg but told the Daily Mail newspaper she had her heart set on reaching her goal weight of 1000lb (450kg) in two years.
The 42-year-old already holds the title of the world's fattest mother after giving birth to her daughter in 2007 when she weighed 241kg.
"I'd love to be 1000lb ... it might be hard though, running after my daughter keeps my weight down," Ms Simpson told the Daily Mail.
Ms Simpson, who needs a mobility scooter to go shopping, eats huge amounts of junk food each week and tries to move as little as possible so she doesn't burn off as many calories.
"I do love cakes and sweet things, doughnuts are my favourite," she said.
