Band slippage was my biggest concern as well. I asked Dr. Miranda how I would know and she said that you would be vomiting all the time.
Of course then I asked Dr. Ortiz and he had a whole different answer:
If I eat before 21 days my band will slip, if I don't call him if I have a problem, the band will slip. And finally.....If I don't treat my husband well and make his every fantasy come true...the band will slip.
In other words, I think you're ok