听力原文：Health food gained popularity when people began to think more seriously about their physical well-being. The well term 'health food' is ironic because it implies that there's also 'unhealthy' food. Health food includes natural food with minimal processing, i. e. , there are no preservatives to help it last longer or other chemicals to make it taste or look better. Most health food enthusiasts are vegetarians: They eat no meat; they prefer to get their essential proteins from other sources, such as beans, cheese and eggs. ______