Grace,
I slowly found that I increased my portion size to about a cup per serving as I progressed to pureed foods and beyond. There are a couple of things that I kept telling myself during this time.
1. Stop eating when I begin to start feeling full.
2. This is not the time to lose weight, just time for my body to heal.
If you remember those two things then I’m sure you will be fine. I don’t think you will stretch the band by going to a cup of soup. As I was told by another bandster, if you follow the diet and do your best then you will be fine in the long run. Good luck!!