That's what a new study published in the Journal of the American Medical Association apparently suggests. We may have hit the biological limit on how fat we can get: virtually everyone who is going to be obese, already is. Obviously, this is not terrific news, especially in a country as opposed to body fat as ours. But it suggests that, as usual, panicking over mindless trend extrapolations might be a little premature.
This suggests a few things. One, that the rest of the world will eventually catch up to us (aside from small populations that are thought to have selected for thrifty genotypes during a fairly recent population botleneck, which will surpass us--and a few populations that may lean the other way.)
Two, that we'll at least be able to see now whether our interventions are working; if the rate of obesity actually goes down, it works.
Three, if we can't make any measurable change, perhaps we can finally switch towards encouraging healthy lifestyles rather than making unrealistic promises about making people thinner.