@dlowan,
I can absolutely see how soda could be a big part of the american diet and where the majority of people get their calories from.
Soda is like water to some, and even more people will out right tell you " I cant do with out my diet coke, or Mountain dew, or Coke," or what ever they drink.
Most sodas have servings that according to the can can number 2-4. And each serving is about 100 calories.
People drink that instead of water. Constantly.
If you go to a fast food place, well you are going to eat several thousand calories at once there no matter what, BUT, if you want to count the servings in the soda alone I would be willing to bet it would be close to 500 for a medium drink and twice that for a large/supersize/giant drink.
It is also common for people to order 'diet' drinks with fast food. Sometimes , ( not always) the diet drink can have MORE calories and sugar substances in it then regular.
but, thats american soda consumption for you.