Here are some examples of what was once a poor man's food and is now a luxury food: 1. Lobster: In the past, lobster was considered a poor food and was even used as fertilizer.

However, due to its unique taste and rarity, lobster has now become a luxury delicacy, with a relatively high price.

2. Mutton: In some poor areas, mutton was once a common food, but as time goes by and people's living standards improve, mutton has become more and more expensive and is now regarded as a high-end delicacy.

3. Bird's nest: Bird's nest was once an important source of nutrition for some poor families in Asia, but as its medicinal and beauty benefits were discovered, the price of bird's nest increased significantly and it is now considered a luxury product.

4. Truffles: In Europe, truffles were once considered a poor man's food, but as their rarity was discovered, they are now a luxury dish in high-end restaurants.

5. Abalone: ??In China and other Asian countries, abalone was once a cheap food, but due to its delicacy and rarity, it is now considered a luxury food and is expensive.

The changes in these foods illustrate that with economic and social development, people's values ????towards food are also changing.