What Causes Passing Of Stool Immediately After Having Food?
It is due to gastrocolic reflex - not a cause of concern
Thanks for asking on HealthcareMagic.
There is a phenomenon called gastrocolic reflex which may make a child pass stool after each feed. It generally subsides after infancy but may occasionally be present for longer periods. It is normal and nothing to worry about. Let me assure you that it is not the cause of your child's low weight.
I would suggest you to get his weight every three months and to plot it on a growth chart appropriate for his age. If the weight follows the lines of the growth chart, even if the weight is on a lower percentile, it would not be something to worry about. However, if there is a drop in percentiles, suitable interventions would be needed.