healthy way to lose weight during pregnancy

Help! Is there a healthy way to lose weight during pregnancy? I've never been really skinny. But I gained a lot of weight during my first pregnancy with my son and I never lost the weight after. I'm now at 196 pounds and on my second pregnancy. I'm so worried... I don't wanna gain anymore weight cause I'm afraid I'll never lose it! My obgyn only want me to gain between 10 and 20 pounds but I don't even wanna gain that.. I want to make sure my baby's healthy but I want to try to lose weight at the same time.. any suggestions?? I'm 11 weeks 3 days