Al-Kāfi - Volume 6 > The Child of Adam is Hollow; thus He must Eat Food
Hadith #3

مُحَمَّدُ بْنُ يَحْيَى عَنْ عَلِيِّ بْنِ الْحَسَنِ التَّيْمِيِّ عَنْ جَعْفَرِ بْنِ مُحَمَّدِ بْنِ حَكِيمٍ عَنْ إِبْرَاهِيمَ بْنِ عَبْدِ الْحَمِيدِ عَنِ الْوَلِيدِ بْنِ صَبِيحٍ عَنْ أَبِي عَبْدِ اللَّهِ ( عليه السلام ) قَالَ إِنَّمَا بُنِيَ الْجَسَدُ عَلَى الْخُبْزِ .

3. Muhammad ibn Yahya has narrated from Ali ibn af-Hassan al-Tamimiy from Ja‘far ibn Muhammad Hakim from Ibrahim ibn ‘Abd al- Hamid from af-Wafid ibn Sabih who has said the following: “Abu ‘Abd Allah, ‘Alayhi al-Salam, has said, ‘The body is made out of bread (food).”’