To lose 1 pount in weight you need a deficit of 3500 calories.
Deficit = to take in less than you expend through exercise / your body doing its daily stuff (keeping you alive). Most people struggle to reduce their intake by 500 calories a day to shift the 1 pound a week.
When starting a diet people usually make quick gains for a week or so
You must have one crazy diet at the moment to be able to lose 10 pound a week when you cut the crap out
It would make an intersting thread on here as I am sure you are not alone in wanting to shed the pounds on the run up to summer