They made a friend of mine vomit, its one way of loosing weight!!
Only joking, they really are the worst things to be doing to your self and are full of nasty chemicals and excessive amounts of caffine, but if you want the shakes and the runs at the same time then go ahead!!
Can I recommend weight watchers if you are serious about loosing weight. I lost 1 1/2 stone over a couple of months and hardly noticed the change in my eating habits, was never hungry, had great skin and my husband siubsequently lost weight also as I just gave him the same dinner I was having.
Good Luck