Against Excessive Fasting

Rav Yaakov Yosef quoted a letter that the Baal Shem Tov had written to him, advising him not to engage too much in fasting and self-affliction, because such practices lead to depression or anger. The main reason to avoid them, the Baal Shem Tov wrote, is that instead of improving a person’s service of Hashem, they keep him from learning Torah and serving Hashem properly.