Ibn Abbas (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) said: "Whoever becomes absorbed in eating clay has helped against himself."
This Abdullah bin Marwan is majhul (unknown), and its meaning has been narrated through another chain that is also unknown.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الضحايا / 19718