Ibn 'Umar (May Allah be pleased with them) reported:
During the lifetime of Messenger of Allah ﷺ we would eat while walking and would drink while standing.

[At- Tirmidhi].

وعن ابن عمر رضى الله عنهما قال:كنا نأكل على عهد رسول الله ﷺ ونحن نمشى ، ونشرب ونحن قيام. .