Good luck with your new lifestyle change.
One of my GF's did Tony Furgerson. She lost 7kgs and then when she went off it she put the weight back on plus a little bit extra.
You are right when you say you can't keep it up for ever, but I think it's good to give a kick start. And there is nothing better than seeing the numbers on the scale going down to give you motivation to keep on going.
Start weight - 77kgs
Goal weight - 53kgs
Current Weight - 50.1kgs
No more weighing, no more scales. My measurement is my success at health. It's an investment I make every single day. My priority: be healthy!