The 22-year-old actress resembled a child – making her look like the younger sister as she and 15-year-old ALI went on a shopping trip in Los Angeles.
The sexy curves that made Lindsay famous have been replaced with protruding hips and boney knees.
An onlooker said: "Lindsay's clothes were literally hanging off her frail frame.
"She looked desperately in need of a burger or two."
On the plus side, it looks like things are improving on the job front.
Li-Lo has landed a role in new comedy The Other Side alongside WOODY HARRELSON and ALANIS MORISSETTE.
The star's mum and manager DINA said: "It's a wonderful cast and it's shooting on the East Coast, which we are so excited about.
The film - Lindsay's first major role since I Know Who Killed Me in 2007 - sees the star play a graduate who discovers a secret tragedy on a remote island. Sun reported.
Director David Michaels said: "Lindsay's very aware of people's perceptions of her.
"She's really committed to doing what she has to in order to change that."