(Do I have to say how much this will vary by the person?)
There are a few things involved in being full: Satisfying your need for nutrients, satisfying your need for sugar and salt, and getting bulk in your gut. If you eat something like a thick bean soup, even if it’s bland and generally not nutritious, it will take the edge off simply by virtue of physically filling your stomach. If you eat a salty but generally watery soup, it will satisfy your need for salt, but it won’t fill your gut and you’ll need some water to balance out the saline in your bloodstream. Either way, you’ll need water to balance out the glucose levels.
Water in the soup will help with the bulk until the next time you urinate. It will also help you balance out the salt and the glucose. Water is good. Water is not really nutritious, but it will take the edge off.
Eat the soup, but don’t be surprised if you want to eat the moment you get home.