Well, what I ate during my pregnancies is probably about the lowest that I would ever recommend. The level that I was eating at was to try to stay the same weight during the first trimester, and to gain the recommended amounts during the second and third...as well as keep my blood sugar and the baby's size under control.
As far as exercise-I HIGHLY recommend it. It helps prevent back pain, helps keep you stronger and fitter with more stamina-so that you are better equpped to handle the demands of labor and delivery. Also, if you stay fitter, you are going to look better immediately after the baby is born, and have an easier time getting fit. If you don't exercise during your entire pregnancy, then after the baby is born, you are not only dealing with extra pounds...but the fact that everything has turned to "Jell-O" from inactivity.