I've always heard that there were a few Europeans countries that were fatter than the U.S., but my Biology professor recently told our class that the vast majority of Europeans countries use "self-reporting" surveys to gather data, unlike the U.S. that uses actual measurements recorded by an interviewer (New Zealand, Great Britain, and Australia are the other three that do this).
So pretty much the difference is:
"Please write your weight here ________"
"Step on the scale, sir..."
This article shows that there are five Europeans countries that are "fatter" than the United States (one is Germany), but the fact that self-reporting isn't very accurate or reliable makes me think that most of Europe has just as much of an obesity problem as we do.
As all doctors and scientists know - every patient lies.