Since the 3 first days of Lent are over, well, at least in Europe, here is a translation from "Le typikon décrypté" by Job Getcha, also available in Englidh the Typikon decoded. Excellent book by the way.
"The Palestinian tradition, (kept in the monastery of Saint Sabbas and the cenobium of Saint Euthymus) will adopt a stricter practice. It will make the integral fast last longer forbidding the consumption of any food until Wednesday and even Friday for those who are able. Consequently, no communion is possible before Wednesday or Friday from this comes the Sabbait practice of celebrating the Presanctified twice a week [note of the translator : and not daily as in other practices that no longer exist].[...] It is important to note that this practice is still kept almost universall in monasteries, where there is no meal until the end of the Presanctified, and where al monks that are able, do not eat and drink during three days (trimeri). Among the laymen, the first day of Lent is also strictly observed"
Page 191 in the French edition
Personal commentary: I personally knew a family in France, a widow in her 50s and her son between 20 and 30, who kept this practice the whole week but after Wednesday, they allowed themselves to drink, if I remember correctly. Other sources told me that the practice was not unfamiliar in 19th century and early 20th in Greece and Romania, in Romania even by field workers (with one person from Monachos forum remembering that her late mother indeed respected the trimeri).