Hi, My 8 Year Old Daughter Has Been Experiencing Fever

Hi,
My 8 year old daughter has been experiencing fever along with diarrhea. Today is her fifth sick day.
She doesn't have signs of dehydration. She is been having small sips of Pedialyte and water.
Her appetite is very low.
The pediatrician's diagnosis was gastroenteritis. How long will this condition last? What food should she have?
I appreciate your advice.
Thank you