A guy I know fasts on Lent “Fish Days” (Ash Wednesday & Fridays) from food altogether, he drinks coffee to get him through the days. I had previously wondered about this as well but defer to the no meat standard, liquids are a differnet story.
This is not explicitly to you, Kenny, but your post provides an appropriate lead in to what I’m about to say…
True liquids, those without “weight” or “substance” such as a milkshake or heavy smoothie, would not count as breaking a fast. This is because over the years as hunter gatherers, we did not have liquid which contained calories (water only). As a result, our bodies have adapted to consider any true liquids as non-energy… in other words, drinking a cup of coffee, milk, soda, tea, etc, will not do anything to satisfy hunger. In fact, out of those, coffee and tea have almost no calories anyway… they’re nothing more than flavored/“dirty” water.
The point of fasting is not to punish onesself, it is to promote penance by inducing a SLIGHT discomfort… a SLIGHT sense of hunger throughout the day that serves as a constant reminder to consider Christ’s sacrifice and discomfort, and thus to tie more deeply into the passion of our Lord. We can CHOOSE to inject aesthetic practices as well, but that’s not the sense interpreted by the church as the ultimate goal here.
As to what liquids WOULD seem to violate a fast, anything with substance which the stomach might interpret as food, and thus reduce the slight since of discomfort would obviously accomplish that. Another shady area that I would say violates the basic principle of fasting would be to consume diet pills or liquids which supress the sense of hunger and thus eliminate that condition which provides our constant reminder.
Remember, lent is not a game to score points by just how much aestheticism you take on, or by how much you give up. The goal is to promote a more constant state of spiritual meditation and communion with Christ by removing something that gives us comfort so that its absence serves as a reminder to ponder the spiritual.