As much as possible, yes. Many American schools offer Free Breakfast and Free Lunch programs for children whose family income qualifies their need. Some high schools (a school in Ohio is an example) also offer additional nutrition to pregnant teens. School breakfasts and lunches are under upgrading evaluations uinder the Obama Administration.
Homeless Shelters offer tutoring, school classes on site, and meals and many of these are healthy, according to Fed, State, and Local rules. Not all are healthy, surely. Kids not in the shelters usually do not receive adequate nutrition.
During summers, a Free Lunch Program Monday through Friday is supported though Federal dollars given to counties and distributed to non-profit agencies. These meals must meat nutrition guidelines set by the Feds. Famileis need to apply in the early spring for the Summer Free Lunch Program - look at community agencies and churches, rec centers, etc. for announcements.