It was narrated from Jabir that the Messenger of Allah ﷺ said:
“Whoever is invited to eat when he is fasting, let him accept the invitation; and if he wants to let him eat, and if he wants let him not eat.”

حَدَّثَنَا أَحْمَدُ بْنُ يُوسُفَ السُّلَمِيُّ، حَدَّثَنَا أَبُو عَاصِمٍ، أَنْبَأَنَا ابْنُ جُرَيْجٍ، عَنْ أَبِي الزُّبَيْرِ، عَنْ جَابِرٍ، قَالَ قَالَ رَسُولُ اللَّهِ ﷺ " مَنْ دُعِيَ إِلَى طَعَامٍ وَهُوَ صَائِمٌ فَلْيُجِبْ فَإِنْ شَاءَ طَعِمَ وَإِنْ شَاءَ تَرَكَ " .