I don't have any hard data for you but I believe you're right about the portion control. Junk food is also popular in Japan, though probably not as much as in

I don't have any hard data for you but I believe you're right about the portion control. Junk food is also popular in Japan, though probably not as much as in the US. However, in general portions are smaller here in Japan and people don't drink soft drinks all day. Apparently the average American geek needs as much food as a Japanese construction worker.