Yeah, Chaqa, you really don't get to just redefine words from how they are and have always been used because it lets you criticize people you want to criticize.
A very small number of people fast -- in the sense of eating nothing at all -- for a large number of days in a row. That is, of course, extremely unhealthy, and the bulk of religious organizations would discourage it. However, the "few hours" (24, specifically) a doctor might ask you to fast is also, yes, a fast, and a religious fast could also be that short. And a fast can also be, as here, a major cutback or change in eating patterns for a period of time for religoius or ceremonial reasons.