The Prophet (ﷺ) said:
“Whoever does not give up false speech and acting upon it, Allāh has no need of his giving up his food and drink.”
Al-Bukhārī, 1903.
Keep the tongue busy with the Qur’ān and dhikr (remembrance of Allāh). And if you’re provoked, say
"إني صائم، إني صائم"
“I am fasting, I am fasting.”