If money was donated to charity everytime someone asked "can i really eat this much and still loose weight?" just before their first weigh-in who then goes home to find that they have lost - there'd be a very rich charity out there somewhere...
I was the same (and still am sometimes - even after nearly 23months on the plan) - my first week - i ate loads - though never deviated from plan, and always had my 15syns. Thought i may have lost 1 or 2 lbs when i got on the scales. Lets just say - i lost a lot more then that - a whole stone had gone. When i looked down at the scales and saw the same "8.5lbs" - i was disappointed - i thought i had maintained. Then the weigh-in lady gasped and said "you'd lost a stone". I was flabbergasted.
OK, that's the more extreme end of the scale of first week weight loss - and there's no two ways of putting it - i had a lot to loose. but yes - you can eat loads (my plates where piled HIGH) and loose weight. Over time the appetite does come down and you will find yourself naturally eating less anyhow.
Enjoy and hope you have a good result at weigh in.