I am always a bit amused when discussions start up about fasting, and “bread and water” is brought up.
In Oregon, Bull Run water off the side of Mount Hood is among the more pure sources of water available within the US; and the biscuits from Red Lobster (with the packaged version available at Costco) are an absolute delight - as well as artisan breads from any bakery worth their salt.
Hardly what I would call a sacrifice.
A fast, according to the Church, is one main meal, and two others which together equal a second meal.
One, of course, can be more strict than the Church; and I will leave it to others to determine whether it is the individual who is wiser, or the Church with centuries more experience - and presumably wisdom. However, one venturing into serious spiritual exercises such as strict fasting would be well advised to obtain a spiritual director first; and one should not go “spiritual director shopping” until one finds a director willing to advise willy nilly such practices.
It might be pointed out that the Trappists lead a rather austere lifestyle, and it is only after some serious and long guidance that one of them is allowed to be a hermit - an even more austere lifestyle.
Penance and self-mortification are worthy, and most of us could do with a good dose of it. However, it is easy to go entirely overboard in such matters, to the point of far more harm than good to the individual.