Slim-fast is very high in sugar. You're better off using a protein powder or meal replacement powder and make your own shake. Not as convenient, but much less sugar.
If you want a great powder, check out
www.juiceplus.com/+ss59092. This poduct is the next best thing to eating 17 servings of whole, raw fruits & veggies. Best nutritional products out there, with more peer reviewed 3rd party research than any other on the market.
Hope this helps. (oh, my email addy on the site is incorrect. I will fix it, but if you have questions, PM me and I can get you more info.)
Good luck!!!!