My rule of thumb has always been to eat in moderation. With DD1, I gained 20 lbs and was at a healthy weight when I got pregnant. With DD2, I was at home with DD1 constantly and tended to eat a lot more. I started out at a healthy weight with her also, but ended up gaining 87 lbs. With DD3, I was at home with the girls too, but I had a lot of energy with her and went constantly. I ate everything I wanted in moderation. I started out about 40 lbs from my ideal weight and ended up gaining only 7 lbs with her. She weighed 6 lbs, 10.5 oz at birth at 38 weeks. I'm almost 18 weeks with this baby and have yet to gain the first pound. And I'm at where I started at with DD3 also.