The only shakes that I've heard that are low glicemic index are Shakeology.  They won't impact your glucose level.  I personally know 2 people that are diabetic and take them.  You can lose up to 7 pounds in 3 days with a special detox program.

Jessica Campos 

You get a special diet as well:

http://www.blogger.com/blogger.g?blogID=5299958521913688360#editor/target=post;postID=6326296742319573140 

It is foolish to try to lose weight rapidly especially with diabetes because you risk losing muscle. Since muscle is the major user of glucose, decreasing your lean body mass is not going to help your diabetic situation. Go to your dietician who is monitoring your food intake, get a sensible diet and follow it. Also exercise. Every day. That is the best way of controlling blood glucose. Most people who lose weight with shakes or cookies or whatever that promises rapid weight loss then experience rapid weight gain. Be sensible.

I am agree with @Dr. Judith .....contact your dietician and take from proper advice...don't take any risk.