Starbucks has just launched the new, larger than Venti, Trenta sized coffee. The Trenta is listed by volume, as being 916 ml. For us metrically challenged Americans, just how big is it? A quick trip to Google shows that Trenta is 30.9736448 US fluid ounces. According to the infographic below, that's just a bit more than the average capacity of an average adult human stomach.
This is still smaller than the venerable 32 oz. Big Gulp from 7-11 and not even half as large as the chain's 64 oz. Super Big Gulp, but is it overkill? Regardless, I assume that your body will have more problem with the increased sugar and fat content of your yummy Starbuck's breakfast parfait than the amount of liquid its being asked to store.