I don't usually weigh more than 2 stone over my normal weight just before birth so I've never had more than about 4lbs to get back to pre-pg weight, HOWEVER, I'm rather careful with what I eat when I'm pregnant.
I don't diet...I have never dieted, but I do carefully monitor what I eat to make sure it's healthy and not to excess.
I also exercise through the pregnancy too when I can.
Obv, none of this applies 'til 12 weeks when I have both appetite and energy.
With Dd I lost all the weight straightaway with bf'ing and night sweats. With the boys I lost all but 4 lbs with night sweats and bf'ing but it wasn't until I stopped bf'ing that I dropped the extra weight, and it was within the week!
I hope i'm not huge again! (bump wise), I looked like mr greedy last time