Producers outside France do not always force-feed birds to produce fattened livers considered to be foie gras, instead allowing them to eat freely, termed "ad libitum". Interest in alternative production methods has grown recently due to ethical concerns in gavage-based foie gras production. Such livers are alternatively termed fatty goose liver, ethical foie gras, or humane foie gras. The British supermarket chain Waitrose also provides a version of ethical foie gras which it calls (and has been trademarked) "faux gras". This is not to be confused with the American product by the same name, produced by Regal Vegan, which has the US trademark for "faux gras", and is actually a vegan, nut-based spread.