Daughter’s meager school lunch

My middles school aged daughter just informed me that she has basically been eating nothing but bread and water for school lunch over the past school year. Should I try to encourage her to eat more? With all the problems kids have these days regarding weight, I am reluctant to push her to eat  more. I have talked with her about nutrition, but she says she doesn’t like the food in the lunch room and doesn’t want to bring a lunch to school because it is embarrassing. What do I do?