I found this Interesting article over at the Newhouse News Service The writer covers the topic of how Portion size is probably a major factor in the obesity epidemic.

"Portion sizes have increased and there's good evidence that if you give someone a larger portion they will eat more. What's shocking and a little scary is not only do they eat more, they won't report being any more full."

Farley cited a Penn State University study concluding that people have a difficult time eating a normal serving when presented with extra food. In the controlled study, volunteers on average ate 30 percent more from a five-cup portion of macaroni and cheese than from a serving one-half its size. Besides not feeling any fuller, few participants even noticed that the portions had grown.

I have noticed this myself, most recently at a dinner at a seafood restaurant. My wife and I split a meal and we were both stuffed afterwards. I mentioned the fact that I don’t know how a single person could ever finish a platter by themselves. I was also thinking of how these super sized platters might be contributing to some of the fresh seafood shortages. It seems to me that there must be a fair amount of waste involved with dinners that large. And as the article notes even if there is nothing left on the plate does a person really need that much at a single sitting?
I remember reading on why McDonalds came out with the supersize. They discovered that people would be hesitant to order 2 sides of fries but would have no problem ordering a supersized single order and we went right ahead and pproved them right.