I wonder why my baby isn't gaining much weight despite the fact that he drinks a lot of milk, and eats Cerelac twice a day. I expect him to be plump, but he's getting taller instead.

Hi, I think it is because he is gaining height. His fat is not retaining in his body because all that nutrition is going in making him grow tall. And I wonder why you not liking that. The baby fat anyway goes after sometime and is a temporary thing. So, do not worry. Yes, if you think that he is becoming weak instead of being fed well then you should see a paediatrician and seek his advice.