[coldtea]

>Definitely if you trigger insulin response it is safe to say you break a fast, but any caloric intake breaks the fast, even without insulin response.

"Breaks a fast" is meaningless without specifying what we mean by that.

If we mean "breaking fast = you eat something with calories" then yes, but then it's a tautology.

If we mean "insulin response", then there would be other criteria for breaking a fast.

Even traditional religious and cleansing fasts allowed lots of different foods (e.g. plants) and were still considered fasts.

Fast is not some one-size-fits-all word that means "absolutely no calories" during it.

[will_brown]

>Breaks a fast" is meaningless without specifying what we mean by that. If we mean "breaking fast = you eat something with calories" then yes, but then it's a tautology.

Yes...that is how definitions work. Consuming calories triggers a metabolic response and breaks a fast. That is the generally accepted definition of breaking a fast.

There are types of fasts dry fast, water fast, intermittent fast. But the fast part is consistent and means no calories/no metabolic response.

The idea some religion somewhere ate plants only a called it a fast, doesn’t make it a fast. If I consume nothing but sugar and went around calling it a sugar fast, that doesn’t change the definition of fast. Similarly if you have a diet that doesn’t trigger insulin, that is a Dietary ketosis. If you are fasting you will also enter ketosis but since it’s induced through fasting not diet we call it fasting ketosis.

[coldtea]

>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."

[Broken_Hippo]

"The idea some religion somewhere ate plants only a called it a fast, doesn’t make it a fast."

Yes, it absolutely does, and sometimes comes along with abstaining from food entirely for short times. Not only that, but there are usually exceptions for children, the sick, and the elderly. Medical fasting sometimes means "nothing" and sometimes means "clear liquids" or a combination. It all depends on context.

I was raised Eastern Orthodox. Wednesdays and Fridays were supposed to be meat-free days, but fish, eggs, dairy, and oil were fine for most. For 6 weeks before easter, no meat. For a portion of that, you weren't supposed to eat dairy, eggs, or oil either. On Sundays, you were supposed to fast before communion at church - this meant liquids only, no food.

On the other hand, some Muslims fast entirely for a month between sunrise and sunset. No food, no liquids, with exceptions for health, elderly, and children.

Common medical procedures require fasting, but it is different depending on the procedure. Need blood tests? you might be able to have water and black coffee, but other times you wont have coffee. Operation? quit food at a certain time and no liquids at a different time, and the timing varies.

Fasting means different things depending on the context it is used in.