Lady Gaga Obsessed With Her Weight, Claims Ian Halperin Tell All Book

Lady Gaga is "sick and obsessed with her weight," according to an explosive new tell-all book by investigative journalist Ian Halperin.

"Those who have worked with her on tour reported to me that Gaga barely ate for weeks at a time to fit into her costume," says unauthorized biographer Halperin. "One friend told me, Gaga will stare at herself in the mirror for hours on end, analyzing and critiquing her body. It's an unhealthy obsession."

Halperin says Gaga wears outlandish wigs and heavy makeup to disguise the side affects of her Lupus -- a disease she has publicly admitted to battling. "Part of the reason she wears wigs and makeup is because her hair is falling out and she's covered in red blotches, both side effects of the disease."

But her weight and her health are not her only problems, Halperin claims. "Her drug use started young. From heroin to cocaine and ecstasy, her friends say that she has done every drug conceivable. You name it she has done it."

The singer whose real name is Stefani Joanne Angelina Germanotta, has "morphed into this caricature called Lady Gaga, who isn't even a real person. The girl known as Stefi to her friends and family has all but disappeared" Halperin says.

Halperin, author of bombshell tell-all "Brangelina: The Untold Story", reportedly spent 12 months investigating Gaga for his book. He has also written biographies of Michael Jackson and Arnold Schwarzenegger.