Obesity is much more structural than it is personal. That's why it's so depressingly predictable. It afflicts certain communities, with certain socioeconomic characteristics, and it has only really emerged across a certain time period. Those communities contain a lot of different individuals, but their environments and their time and money stresses and their transportation and grocery options and their street safety and exercise opportunities are broadly similar. How we live has changed much more quickly than who we are, and no effort to turn back the tide on obesity will succeed without an accurate understanding of what's made us obese.