Now my baby is one year old .but she is too small . can you explain weight gain foods

A. hi well , first thing need to clear that to look thin or small and to have low weight gain,both are different things. please don't judge child's Health from physical appearance because physique mostly depends on Genetics and it is not necessary for babies to look Chubby it is more important to stay happy and active then any other things so if your child is looking happy and active, gains enough weight, achieve age appropriate milestones then no need to worry about it much