H.J.
I agree with the other responders, that it is best to just continue to focus on being healthy. However, I lost 10 pounds in my first trimester. In the second tri, I maintanied my weight, now that I am 2 1/2 weeks from my due date, I have gained 25 pounds. I do not beleive I am doing anything that different now than in the first tri, but my midwives have never been concerned with my numbers because I was overwheight to start out and I haven't had too many extremes.
I would also say that you should not deprive yourself or let yourself get too hungry, your body is going through a lot and you don't want to strain it. Sometimes hunger can feel like morning sickness too, so try to have a little something even when you don't feel good.
Also, if you have a craving for something, you should indulge in it, within reason. I think our bodies tell us what we need, so if we listen carefully, we can give it the right things. I was craving red meat and then found out I had low iron, so it was good for me to eat it.
Take good care of your body and baby.
Good luck!