Stress also will cause your band to tighten. I was very stressed out at one point and didn't know this. I had other important issues to deal with at the time and didn't pay attention to the fact that I was throwing up all the time. I stretched my pouch and had to let it out for 6 months. During that time I gained back about 60 lbs of the 100 I had lost. I finally got to have my fill and then found out I had to have surgery so I had to unfill. I have had a fill since my surgery but not very much. I gained another 10 lbs and can't seem to lose anything. My doctor says that once you stretch your pouch that the pouch is easily stretched again making it hard to know if you have stretched it or if you need a fill. I am so discouraged and am thinking about having the sleeve done.
My doctor told me the same thing and he said it is because the carbonated gases fill up your stomach and stretch it out. It really isn't that bad, i haven't had one in 4 years. Believe me they are nasty to drink now.