Their argument that knowing your hydration quotient is more important to fitness & wellbeing than knowing your calorie intake should get them pummelled. I don't care if they have an MD on their staff.

For a start if you care about health & fitness to a degree at all you simply wouldn't drink Red Bull, beer to any amount that it makes a difference. If you do it will be in a binge scenario.

I also use the same technique in debate by dealing with likely criticism by mentioning it and countering with a weak counter point. In this case that is the use of the app to enter drinks you would never pour into a horrid big bottle.

I also wonder about the tech they use to determine the liquid content. I'm gonna guess its not that clever. Using light analysis vs a DB of known drinks or something likely to be wrong.