I'm a social worker and believe me I want to do something about obese children but our resources are typically stretched to the absolute limit just handling the most vile, rapey, brutal cases. Obese families really should be encouraged to join/referred to community groups that teach nutrition and exercise to fat families but there's few of those programs around.  Ideally, these kids would be put on strict doctor prescribed diets and the family needs to be checked on and held accountable for following it to the T but we're still a few years away from anything that good.  Once an area is considered to have a particularly bad problem with childhood morbid obesity a community outreach program might be initiated (provided the local council has some shitlords and money to spend on it) but it seems to have to get to disgusting levels first.