The Prophet said: "When one of you is invited to eat then let him respond, if he is fasting then let him pray." Meaning: supplicate. (Using translation from Tirmidhī 780)
السيوطي ١٨٠٨a:
"إِذا دُعِيَ أحدُكُمْ إلى طعامٍ فليُجبْ وإن كانَ صائمًا" .