Meal replacement...is this a cure?!

Hi everyone!!

I suffer terribly for IBS-C and am currently taking Resolor by my hospital consultant.
I suffer constantly from C, ive had impaction a many times before!!
Anyway so I want to lose weight and chose to try Slim Fast meal replacement shakes; and since I've started them (a few days) ive been having daily BM (this hasn't happened in years!!) and im finding that I am full but no longer feel bloated and horrible!!
Has anyone else ever tried anything similar?!
You have to make them with skimmed milk, but the milk isn't upsetting my stomach at all!!
Thanks
Emily