The Winter's Bone star plays shapeshifting mutant Mystique in upcoming prequel X-Men: First Class, and was required to work-out regularly and eat healthily to shape up for the role.
Lawrence admits she found the regime tough, and she's relieved to be able to eat normally again.
She tells The Hollywood Reporter, "It was awful, I was hungry for five months. I’m still p**sed about it.
"I’m slowly working my way back because I have to be able to eat like an a**hole."