I've only read about half the thread, but just wanted to comment...
I grew up in a large North American city in the 1980s. We were not allowed outside without our parents. We were not allowed to walk to school on our own until we were about 12 - 13 as it was considered dangerous. So not a lot of time playing out.
We had plenty of snack food and never considered that there was a reason not to eat it! What I mean is that there was no moral or financial reason to abstain from snacking. Actually, my Jewish grandparents who had lived through war and hunger actively encouraged snacking. It was a blessing to not be hungry.
As a result we were probably poised for obesity - lots of time indoors, plenty of snacks and no one seeming to care that much what we ate, as long as we ate. This was normal for us. However - no obesity. My sisters and I were and are fine. Today I have a BMI of 21, and it is only at the ripe olf age of 35 that I am noticing I have to watch what I eat. My son eats far too much junk, but he is a skinny little thing who never stops running.
Not sure what my point is exactly, but it just seems wrong to attach moral judgements, outrage and a sense of one up-manship to food choices. Yes, as a species we need to figure out how to deal with surplus calories; calling people lazy probably won't do it. Nor will harking back to a golden era of endless running around and strict rations of meat and allotment veg. Maybe removing emotion from food choices (hard, I know!) will allow people to self-regulate a little bit more easily?