The 22-year-old, who sparked concerns for her health with her dramatic weight loss this year, confessed to embarking on an extreme 'juicing' diet in her bid to stay slim.
"Sometimes it's hard," she told The Sun. "If you open any high-fashion magazine, the girls in it are stick-thin and then they've been airbrushed down to the point where it's just ludicrousness. I have days when I wake up and think, 'I'm so fat'.
"I do juicing. You juice vegetables and then you drink it three times a day. It's gross. I do it usually for about a month.
"I have no willpower but with the juicing I'm like, 'I have to do it because I have to lose this extra ten pounds'. I will lose it then I'm back going mental for the chips."
Geldof earlier this year attributed her slimline figure to a bout of bird flu.