Girl had operation with the help of funds raised by Miley Cyrus

Gentrie Hansen was fitted with a gastric pacemaker — a device that allows her stomach to digest food — in July this year to combat the effects of paediatric gastroparesis.

The disease, which has no known cure, stopped the 14-year-old student's stomach from digesting food because the nerves and muscles did not co-ordinate.

Any food or liquid was rejected by vomiting.

Gentrie told the US Today Show she was an active teenager who enjoyed cheerleading when she was suddenly unable to keep her food down in December last year.

Doctors believed she had a bacterial or yeast infection but antibiotics did not stop the vomiting. In January this year, Gentrie was rushed to hospital with severe vomiting and dehydration.

By February, her weight had dropped from 50kg and 38kg, leading some specialists to speculate that the girl was suffering from the eating disorder bulimia.

"The worst part of my whole sickness was people telling you 'you have an eating disorder' and you know something else is wrong and you really want your food," she told the Today show.

Gentrie eventually had a CAT scan which showed she suffered from paediatric gastroparesis, a condition which doctors believed could have been brought on by a virus.

But the ordeal was far from over — Gentrie was fitted with a gastric tube to help her gain weight, but her body rejected it six times. Botox also failed to treat the condition.

Doctors told Gentrie the best option was a pioneering new treatment — a gastric pacemaker — which could help.

The family raised funds with the help of singer-actor Miley Cyrus and Gentrie underwent the operation in July. She left hospital last week and had her first meal in eight months: a Wendy's hamburger.

"Even a small cracker seems to me like a nice juicy steak, at least in my mind," she said on her blog.