A. We don’t do it very often, but the few Jewish fasts a year are a form of personal suffering to better appreciate and relate to what these fast-days represent. And getting away from food for a while helps us focus our minds on spiritual pursuits such as prayer and reflection. But the truth is this is the exception for Judaism which usually emphasizes finding spirituality within the material. Eating good food is an important and regular Jewish experience.
BTW, we tagged this question under the “Holidays” category, because fast-days are Jewish calendar events, and believe it or not, both Yom-Kippur and Tisha B’Av are considered holidays, though somber in nature, and the Fast of Esther is connected to Purim, and the Fast of Gedalia comes a day after Rosh Hashana.