What does the Qur'an say about all-you-can-eat buffets?

"A leading cleric in Saudi Arabia has denounced all-you-can-eat buffets because customers are not told how much food they will get. Sheikh Saleh Al Fawzan, a member of the Saudi government’s Council of Senior Scholars, said buffets and brunches are un-Islamic as the customer is buying “the unknown”. He denounced “a phenomenon in some restaurants where owners tell their customers: eat what you like from the displayed food and pay a lump sum”. “This is unknown and the unknown cannot be sold until it is defined and identified,” Sheikh Saleh said in a statement on his website." (thanks Basim)