>The idea some religion somewhere ate plants only a called it a fast, doesn’t make it a fast.
Actually it does.
It might not make it "a period of no food consumption at all", but it does make it a fast.
It's not the etymology or scholarly definition of words that dictates their meaning, but how they are actually used by the people speaking a language.
The word fast (and it's analogous in different languages) has been in use for centuries/millennia longer than people actually knowing what a "metabolic response" is -- so such a concern couldn't be part of how they used the term unless until very recently.
As Wikipedia puts it: "Fasting is the willing abstinence or reduction from some or all food, drink, or both, for a period of time".
Notice the "some or all food"?
Here's how the fast period is defined for catholics for example:
"For Roman Catholics, fasting, taken as a technical term, is the reduction of one's intake of food to one full meal (which may not contain meat on Ash Wednesday and Fridays throughout Lent) and two small meals (known liturgically as collations, taken in the morning and the evening), both of which together should not equal the large meal. Eating solid food between meals is not permitted. Fasting is required of the faithful between the ages of 18 and 59 on specified days. Complete abstinence of meat for the day is required of those 14 and older. Partial abstinence prescribes that meat be taken only once during the course of the day. Meat is understood not to include fish or cold-blooded animals."
Actually it does.
It might not make it "a period of no food consumption at all", but it does make it a fast.
It's not the etymology or scholarly definition of words that dictates their meaning, but how they are actually used by the people speaking a language.
The word fast (and it's analogous in different languages) has been in use for centuries/millennia longer than people actually knowing what a "metabolic response" is -- so such a concern couldn't be part of how they used the term unless until very recently.
As Wikipedia puts it: "Fasting is the willing abstinence or reduction from some or all food, drink, or both, for a period of time".
Notice the "some or all food"?
Here's how the fast period is defined for catholics for example:
"For Roman Catholics, fasting, taken as a technical term, is the reduction of one's intake of food to one full meal (which may not contain meat on Ash Wednesday and Fridays throughout Lent) and two small meals (known liturgically as collations, taken in the morning and the evening), both of which together should not equal the large meal. Eating solid food between meals is not permitted. Fasting is required of the faithful between the ages of 18 and 59 on specified days. Complete abstinence of meat for the day is required of those 14 and older. Partial abstinence prescribes that meat be taken only once during the course of the day. Meat is understood not to include fish or cold-blooded animals."