i would think she is spending alot of energy fighting off the infections and so doesn't have a lot spare. Not sure if you weighed her regularly, but has her weight gains been consistent since birth, or is there a point where the weight slowed?

FWIW, my DD was born 3.7kg and at 15 months is 9.2kg. She has gone from 75th percentile to 10th for weight. I am trying to give her little quiches and higher fat foods, but i also recognise that she is just so active and has always been a slow weight gainer. I have read the food you pack for your little one for care, and i don't know how much more you could add, the food is gourmet!