RUMNUT can be used to formulate rations to a range of protein systems; the revised UK MP system (1998-2001), the French PDI system (1989), the RDP/UDP system (Australia 1980), the USA (USDA) system (2001) and a system derived from the UK and USA systems and similar to the FiM proposals (FiMd, 2002). The systems run concurrently and the user can switch whilst running the program either via the main ration status bar or the 'Protein System' menu option.