Sugary drinks are the bulk of the American diet, calorically speaking. I once had a hand in an effort to reverse engineer the Coke formula and make an open source version (led by Amanda Foubister), and the thing that shocked me then was how much sugar goes in a can of soda. Lemme put it this way: if you spooned that much sugar into a comparable volume of coffee, you'd draw stares and laughs. Basically, fizzy drinks are a slurry of sugar (actually, in tinned soda, it's usually high-fructose corn syrup, which is to sugar as plutonium is to oat muffins) with enough liquid to slide out of the can.
Tufts researchers recently reported that while the leading source of calories in the average American diet used to be from white bread, that may have changed. Now, according to preliminary research conducted by scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Americans are drinking these calories instead. The research was presented in abstract form at the Experimental Biology Conference in April of this year and a more comprehensive paper is being developed.Link