My friend did Lipotrim a couple of years back (with my disapproval). It used to be for morbidly obese only, to be prescribed only by doctors, but then it became available to buy in chemists so long as you returned regularly for checkups. She would not have got it had she gone to the dr as she would not have been heavy enough.
It's not even as nutritious as milkshakes, as unlike slimfast they are made of water! She did lose weight quickly but also experienced hair thinning and hair loss, not sure if it ever returned to the way it used to be.
As well as this type of diet, they also have a maintenance plan, where you eat one meal a day, it doesn't make you lose weight but it keeps off the weight that you lost in the first place!
It's a quick fix that used to be used for medical reasons, now it's just seen as a way to lose weight quickly coming up to a wedding or something! It's almost banned in Ireland because of the side effects