> I'm amazed at the sheer amount of dairy that Americans eat.

I suspect that dairy figure is disproportionately milk, which in turn is almost entirely water.

A cafe latte is mostly milk, and Starbucks-style coffee shops sell a 20oz/568ml 'large' size - two of those a day and you are over the average.

(I haven't been to the US for a few years, but I seem to remember Starbucks selling an even bigger size as well)