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. We ask Allaah to exalt his mention as well as that of his family and all his companions.
We do not know any evidence about the Prophet drinking while eating or after eating. However, the jurists stated that it is disliked to drink while eating; their evidence about this ruling is that drinking while eating is harmful. Al-Bayhaqi from the Hanbali school said: 'Drinking water while eating is disliked even if this is not done as a habit because it is harmful.' He further said: 'Ibn Al-Jawzi said: 'Water should not be drunk while eating as this is healthier.'
Allaah Knows best.