David Ciemny makes the claims that the 'Alejandro' singer frequently crash dieted at the expense of her health in upcoming book Poker Face: The Rise and Rise of Lady GaGa.
The Sun reports that the 24-year-old would binge on fast food and then starve herself in order to fit into her stage costumes. Ciemny alleges that GaGa once lost 20lbs between the first and final fittings of one outfit.
He said: "When I say she was sick, I mean physically and mentally."
GaGa has suffered a number of health scares in the past six months, including collapsing on stage in New Zealand and testing "borderline positive" for lupus.
