20lbs loss in 5 weeks - possible?

[1nsom]

Is it possible to lose 4lbs a week, for the next 5 weeks? How difficult would that be?

As usual I've left it all to the last minute!

No, I don't think that would be possible. Well, possible maybe, but not sensible.

Although, I used to be able to lose a stone in a month, being super strict.

You'll probably lose 4+lbs in the first week, but it slows down after that.