Demi Moore will not be told how much she weighs while seeking treatment for an eating disorder, it is reported.

The 49-year-old actress is said to be getting help for substance abuse issues and anorexia at Cirque Lodge rehab centre in Utah.

But RadarOnline claims that the Ghost star will have her precise measurements kept from her so that she doesn't obsess over them.

"It's common treatment practice at Cirque to not allow patients that are being treated for an eating disorder to see how much they weigh when they step on the scale," an insider told site.

"Their weights are taken every day, sometimes several times a day to make sure that they aren't losing weight while in treatment. Doctors at Cirque don't want patients to fixate on their weight.

"People just say Demi should just eat something, well if it were that easy, she would.

"Anorexia is a very serious disease and treatment can take three months before a patient begins to see success.

"She will likely stay at Cirque for at least 60 days. She doesn't have a roommate currently, but that could change though as she advances through the programme."

Demi's weight seemed to plummet after reports surfaced that her husband of six years, Ashton Kutcher, cheated on her on their wedding anniversary. She was rushed to hospital last month after having a bad reaction to something she smoked.