There is nothing called junk food. The problem with obesity lies with children who do not exercise enough.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/sunita-narain-junk-games-and-schoolchildren
[2] http://admin.indiaenvironmentportal.org.in/category/author/sunita-narain
[3] http://admin.indiaenvironmentportal.org.in/category/newspaper/business-standard-new-delhi
[4] http://admin.indiaenvironmentportal.org.in/thesaurus/junk-food
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/centre-science-and-environment-cse
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/sunita-narain
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/obesity
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/children
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/child-health
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/delhi
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/high-court
[12] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ngo