First rule: make backup copy of your save directory to protect it from undesirable changes. If you don't know where it is locating – create new game save with custom name and search local discs for file "<your_save_name>.sav"
Before using debug menu you need to activate it first.
Find the installation directory for Oxygen Not Included game. Create empty text file inside "OxygenNotIncluded_Data" directory inside game folder. Change created text file name to "debug_enable.txt". Make sure .txt is the extension and not a part of the file name. Restart Oxygen Not Included.
Backspace – Reveal all asteroid map & open debug menu. You able to insert all available liquids, gasses, change temperature of any tiles, buildings, surroundings. Clear debris on the floor or destroy some undestroyable objects like computer desks, vents, geysers, chunks of neutronium, etc.
CTRL + F4 – Instant build. All unresearched buildings become available. Place what you want and it will instantly be built without using up any existing resources. Instant dig.
ALT + Q – Teleport selected item to mouse position (usefull for flying critters and for dupes who trapped themselves).
CTRL + U, ALT+Z – Ultra Speed. Toggling this mode on makes the game run as fast as your computer's CPU can handle. Not recommended. May cause problems with emulation of physical processes.
CTRL + F2 – Spawn random duplicant at mouse pointer.
CTRL + F5 – Toggle extra slow game speed (I can't imagine why you would need it).
CTRL + F9 – Discover all elements.
ALT + F1, ALT + S – Hide/show user interface, super zoom. This is very useful for screenshot purposes. Also unlock the camera, so you can zoom out more.
Oxygen Not Included cheat food
There is no cheat to instantly add food in game but you may use debug menu to insert template file.
Downloat this file and paste it to "OxygenNotIncluded_Data\StreamingAssets\templates" folder inside game folder. Don't change content and extension .yaml. Restart the game and using "Backspace debug menu" paste BBQ into place you want.
In case you preffer non-perishable Berry sludge use this file instead.