Only lost 1 kg in a week on 1200 cal diet!?

HelP! Why did I only lose 1kg in a week of eating 1200 calories (exactly cos I get the food delivered by a diet company) when I used to eat 3000 calories a day~!! I thought I’d drop 5 kgs straight up! I’m 168cm and 75kgs. WHY !!!

http://ping.fm/zWbV1