I am currently 16 weeks and have lost 9kg. I'm overweight and my ob is happy with this. Our goal is for my weight to remain the same or less as pre pregnancy. I haven't really tried to loose weight while I haven't been sick I haven't really felt like eating. Our bub is growing well so I guess that is also a consideration.
I think the recommended weight gain for obese women is 5-9kg so once you factor in a 3kg bub plus placenta and amniotic fluid you are pretty much only gaining bub + a couple kgs if not loosing a little.