she moves too much, or horizontally challenged

so the baby likes pasta, and hot dogs, and bananas. she still has yogurt for breakfast but the rest of the dining experience has changed. we went to the doctor for her 9 month checkup and she has dropped from the 25th to the 10th percentile in weight. the only way i got out of the office with my pride was that she stayed in the 50th for her height. she is growing, just up and not out. they want me to start milk and try to get her to nurse more. i swear i feed the baby, i do. she  moves too much. i think we should work on getting her to move less instead of trying to feed her more. dont they say to exercise more instead of concentrating on diet? shouldnt the opposite be true? any ideas on how to stop the baby from moving? anyone?