I think babies look chubbier as long as they are being breast fed.
A child is usually weaned by 12-18 months. This coincides with the spurt in vertical growth and often gives the visual effect of the baby thinning. She also stops gaining weight at the same pace as before (upto 12 months ranges between 1kg to 0.5 kg a month, post that it is about 0.25 kg a month)
I have observed it in almost all the babies in my building and there are many of them.
And note I highlighted look chubbier - because weight wise there is no cause of concern and they may even be above the average.
What do the other moms out there think?
This post is credited to a casual comment by Kid in the previous post.