Is is permissible to eat whily lying down

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.

The jurists stated that it is disliked to eat while lying down, and they reported that some scholars of the Salaf (the righteous predecessors) disliked this out of fear that by doing so, their stomach would become bigger, in addition to this being against modesty and humility. 

For more benefit, please refer to Fatwa 116244.

Allaah Knows best.