@BestReplay, it could be multiple things..
1 - Go into Prison Running (right on D pad) and view Logistics. You can then view the Catering option. This will show you the supply lines for food - showing what kitchens serve which canteens and which cells go to which canteens. If you do not see that you have these established check the list below for possible issues. If you have good logistics skip to #2.
- Verify you have Kitchen & Canteen
- Verify you have path from delivery area to the kitchen, from kitchen to canteen and from canteen to cells (must be able to get ingredients from trucks to kitchen, food from kitchen to canteen and prisoners to the canteen to eat)
- Verify you have Cooks hired to cook in the kitchen
- Verify all of the above rooms meet their requirements (no exclamations warnings on any of the rooms)
- Verify the kitchen items have power and water as required
- Verify your power is running properly - otherwise they cant cook food
- Verify your water is running properly - otherwise they cant wash and have items available to serve food
2 - If your logistics are good, and your prisoners are not leaving their cells to go eat, you probably have one of the problems listed below.
- Verify you are not under lockdown! Lockdown locks all doors and they cant move around. Check under Emergencies. Will also be flashing red icon in bottom right corner indicating it is on.
- Verify you are not under Bangup! Bangup sends all of your prisoners to their cells to be locked in until you turn it off. Check under Emergencies. Will also be flashing red icon in bottom right corner indicating it is on.
- Check your Regime (under Reports - Up on D pad). Each prisoner level (e.g. Medium, Minimum security, etc) has their own schedule which you set under this Regime menu. You need to verify you have set a time window for every level of prisoner you have to Eat. If you don't have a time to Eat they won't go to Canteen (and Cooks will never cook food, as there is no demand for it.)
- Check your security setup under Prison Sectors (right on D pad). This area gives you the option to set rooms/sectors as only for certain security levels. Make sure that your Canteen is set properly (usually to Shared [Default]) otherwise the prisoners of the wrong security level are not allowed in the room, so they won't go eat. Also make sure they have a route to the Canteen that their security level is allowed to take.
Hope something in the above helps resolve your issue!
Cheers!