Hi weightlossbabe and welcome to BellyBellyy!

I was taking Optifast supplements for about 6 weeks. I didnt replace all 3 meals though, only 1 per day actually. But I made sure I ate healthily for the other 2 meals as well. In about 6 weeks I managed to lose 5 kg... and the great thing is that the weight has stayed off.
I would have kept going for longer except that I ended up getting pretty sick of the drinks and just wanted to be able to eat solid food again...