Not true. I practically live on Diet Mt. Dew.
The no sugar thing is true for some people. It is advised not to eat it or it can cause you to dump as it gets passed through the stomach and intestines quickly and its ugly. It happened to me in the beginning but only sometimes now. I still try to limit my sugar intake though as I know I don't need it.
A good website for some FAQ's is:
www.obesity-surgery.net the surgeon that did my surgery this is his website.
Jbug