After each of my two pregnancies, I lost all the weight I gained in 3 - 4 months. But the first one was not very healthy. I lost it because of sleepless nights caring for my eldest since she was a colic baby. She had kept me up all night! So without knowing it, I just lost all the pregnancy weight I gained. But I cannot remember anymore how much I had gained and lost. My second post-pregnancy weight loss was more ideal since I cut back on food intake and exercised. So it was healthy. After several years when I'd gained weight again, I lost the extra 5 kilos in over a month. I really took my time as I lessened my food intake gradually. I watched what I ate like removing all my junk food then I ran/walked about 2-3x a week.