Earlier quoted context omitted.
But his question was "why in America?", why not anywhere else?
It's not only in America anymore. I've seen just as gigantic portion sizes while traveling to Europe (England, Netherlands, Romania, Italy, France) and Australia, though not so much in China (except Macau). Likely other countries are moving in the same direction as America. At restaurants, however, there is very good incentive to provide large portions. A restaurant has fixed portions that need to feed everyone from…
None of these places have anywhere near the same portion sizes.