Supersize kids may help.
http://www.supersizedkids.com/
The book -- Food politics -- esp the school nutrition bit. Some kids rely on school breakfast and lunch, and when school is NOT in session... go hungry or eat crap.
http://www.foodpolitics.com/
You may consider neighborhood safety too. Because some parents rather keep the kids inside playing video and maybe eating crap than let them run around playing outside because the neighborhood is not safe. Between the two options, fat ALIVE kid is better.
Or the angle of food access -- some neighborhoods HAVE no access to a decent grocery. What can you get besides mc'ds and the corner convinience store? Look up west oakland -- people's grocery and mo' better foods, "grub" coop and other info is available on improving food access.
A.