I'm from the largest dairy exporting country in the world, and I consume about 1/4 the amount of dairy as an average American.
I suspect that dairy figure is disproportionately milk, which in turn is almost entirely water.
(I haven't been to the US for a few years, but I seem to remember Starbucks selling an even bigger size as well)
I suspect that dairy figure is disproportionately milk, which in turn is almost entirely water.