Fasting means a person is permitted to eat one full meal. Two smaller meals may also be taken, but they are not to equal that of a full meal.
Since there are no guidelines as to what one full meal means, therefore how long one can engorge oneself remains uncertain. Would it be against the rule to sit down at a buffet for hours, say from 2pm to 5pm, which combines breakfast and dinner into one full, very full, mid-day meal? It is technically just one meal, engorged in one sitting with countless intermittent refills, so it could be considered as a one-meal fast.
That probably contradicts the spirit of fasting. If so, then what is the spirit of fasting? Is it just about skipping meals? The Catholic Church says yes, but can it go further than not eating throughout the day?
What about abstention from worldly concerns? Can the entire Catholic clergy forget about status, power, internal and world politics [2], budgets, fund raisings and collections but pray instead to "sanctify the Church" (words quoted from the first reading Joel 2:12-19, Extraordinary form Mass) [3]? The passage also says this, quoted without references [4]:
Between the porch and the altar
let the priests weep,
let the ministers of the LORD weep and say:
“Spare your people, LORD!
do not let your heritage become a disgrace,
a byword among the nations!
When has anyone seen a priest or a minister of the LORD weep, on Ash Wednesday, Good Friday, or on any day during Mass at the altar of sacrifice?
The day all priests and ministers of the Lord weep will be the day the entire Catholic Church will be sanctified. Perhaps some wolves in sheep's clothing may start to weep when they face an irrevocable eternity in Hell.
[1] https://www.thecatholictelegraph.com/refresher-on-the-rules-of-fast-and-abstinence-during-lent/21603
[2] An example of pope and clerics meddling in world politics - http://www.usccb.org/news/2020/020-21.cfm
[3] http://www.extraordinaryform.org/propers/LentAshWednesday.pdf
[4] http://www.usccb.org/bible/joel/2, 17.