Legal analysis: prisoners in prison have three meals a day. It's just that the food in each local prison is different, but it's basically the same. There's not much difference, but the prisons in the north and the south probably focus on different things.

Legal basis: People's Republic of China (PRC) Prison Law.

Article 4 A prison shall supervise prisoners according to law, organize prisoners to participate in productive labor and provide ideological, cultural and technical education to prisoners according to the needs of reforming prisoners.

Article 7 A criminal's personality shall not be insulted, and his personal safety, lawful property, defense, appeal, accusation and other rights that have not been deprived or restricted according to law shall not be violated.