It CAN be done.
It just takes a HECK OF A LOT more PLANNING and commitment.
That weight-loss has to be SUPPLEMENTED with serious Protein intake to compensate and ensure no muscle mass is lost.
At 258lbs, losing 3lbs a week IS a lot.
With a goal of 225 thats a loss of 58lbs in in 14 weeks or FOUR POUNDS per week.
Seriously though
This is a SUPER AGGRESSIVE schedule.
I would not put someone on a -4lb/week schedule who wasn't over 350lbs, and 400lbs would be better.
On a normal basis, this is the weightless schedule for someone weighing in at FIVE HUNDRED POUNDS, where the standard goal is
-50lbs in the first 90 days.
-45lbs in the second 90 days
-40lbs in the third 90 days
-36lbs in the fourth 90 days
For a total sustainable loss of 171lbs in a year.