Here's an extract from the provincial circular of GBR for the month of March 2017:
... a warning to us about misplaced mortification. 'A want of moderation in the use of fasting, discipline and austerity,' Francis (de Sales) states, 'has made many a one useless in works of charity during the best years of his life.' and he cites the example of St. Bernard who, repented of his excessive austerity. Like Don Bosco, Frances de Sales was against long and immoderate fasting, especially for the young. He states 'a constant habitual moderation is better than occasional abstinence alternated with great indulgence.'