I as a practicing doctor was amused by the discussion about weight loss.It is good to know how many of us want to lose weight though no one listens when we advise them not to gain weight in the first place.
Once you have gained weight and want to lose it.you certainly can.
You must understand that women gain weight during pregnancy which is natural.It is to prepare them to feed the baby later.
But what happens after that,i am writing this in Indian context,is that the new mother is fed all the fattening foods and not to do anything,forget regular exercise

Once you want and have decided to lose it,remember,you can not lose weight by eating something but by not eating so many things!
As weight loss program has to be individualized,you should consult a dietitian as the diet varies according to your age,weight,amount of work you do so on and so forth,and if you don't get to talk to a dietitian go to your trusted family physician and they can certainly guide you.
Beware,weight loss methods can never be generalized.
Good luck