Megan Fox's personal trainer has dismissed rumours that the actress is suffering from anorexia.The beauty has come under attack in recent weeks for appearing gaunt and skeletal in a new ad for Armani.

However, Harley Pasternak has claimed that his client struggles to gain weight because of her 'fast metablisim' and insists she is not suffering from anorexia.

"She gets frustrated at times because she''s like "I need to put on weight." So she actually weight-trains to keep on that lean muscle tissue," the Daily Mail quoted Pasternak as telling America''s Hollywood Life.

"Believe it or not she has this really fast metabolism. So her training is all about body toning and sculpting. With her its really about she's eating enough of the right things.