Practically the ‘fasting’ or ‘vrat’ is a part of the ritual and begins as a prelude to Maha Shivratri on ‘Trayodashi’, that is on 10 March itself. It includes eating only one time.from Top Lifestyle News- News18.com https://www.news18.com/news/lifestyle/maha-shivaratri-2021-foods-that-you-can-have-while-on-fast-3521555.html