Hi. I have been on the Optifast diet now for 4 weeks. I have been walking, Bike riding, doing aerobics, at least for an hour two times a day and drinking at least 2 litres of water a day. Sometimes doing 2 (eg: walking and aerobics) at a time. All I have is the shakes for breakfast, lunch and dinner plus my 2 cups of vegies allowed in the optifast diet and the 2 litres of water a day. I have not weighted myself for the last 4 weeks (4 weeks ago i was 91kg, with a height of 5 foot). I weighted myself today as I was feeling I have not lost weight and weighed 92Kg. I could not believe that I have not lost weight but put it on? What is going on? I have stuck to the diet and trained hard with no results. I am very disappointed. What could it be that I am not losing weight but putting it on. I used to be 55 kg, even after my first child. This is not me!!!!!!!