my baby is completed 8 month her weight is 5.6kg she is very thin how can I gain her weight

A. dear mum , was the baby ptemature n low birth wt as it can affect catchup growth n wt gain follow the growth curve with doctor give 3 meals consistency of food like ghee dal , khichdi, veg fruit egg , chicken , curd add powdered nuts n ghee continue breastfeed