Article 2 of the Regulations of People's Republic of China (PRC) Detention Center is an organ that holds criminals who have been arrested according to law and criminally detained.
So he's not in jail, it's for public security cases.
Secondly, according to Article 23 of the Regulations of People's Republic of China (PRC) Detention Center, prisoners are provided with food in accordance with the prescribed standards during their detention, and corruption or misappropriation is prohibited.
Generally, detainees are guaranteed to eat healthily and fully. However, vegetables are generally the main food for three meals, and eating meat for two or three meals a week will improve.
Third, those suspected of criminal offences can be detained for up to 37 days, and after 37 days, they can either be released or arrested.