When I was pregnant with DD1, I put on a good 30 kgs... but then I was severely underweight when I fell pregnant with her (still not sure how I conceived, tbh - DH's swimmers must just be determined little buggers), and I did go absolutely mad with the TimTams and KFC while I was pregnant with her...
After I had her I lost about 15kgs, was trying to get back to pre-preg weight but decided to try for another bub (and succeeded straight away), this time around I've only put on about 5 kgs and I'm 23 weeks. I had only put on 2kgs up until a few weeks ago, I was really worried because with DD I stacked on the pounds pretty quick and I was worried that this little one might be starving to death in there, but doc assures me my weight gain is totally healthy and my friends have said I seem to be losing weight from other areas of my body and gaining it in the boobs and belly.