Lichvod Ha Rabbanan,
I read that one should eat a meal of bread or mezonot every morning after davening.Is this a halacha or is it just good advice? If it is an halacha, am I allowed to learn in Shul after davening and before returning home to eat breakfast? Am I allowed to go for a jog after Shul before eating breakfast? Am I allowed to skip breakfast if I overeat the previous night and I am not yet hungry? If I suffer from time to time with irritable bowel, can I skip breakfast so as to allow my stomach a few more hours without food so as to settle?
Tiskeh Le Mitzvot,
The idea of pas shel shacharis — morning bread, or breakfast — is not an “obligation,” but is stated by the Sages of the Gemara by way of good advice. The Gemara writes that no less than 83 ailments are countered by “morning bread,” and a number of additional benefits are also mentioned, such as the ability to focus well on one’s studies, and another twelve benefits (Bava Metzia 107b).
The Tur (Orach Chaim 155) mentions the concept of eating breakfast, and writes that it is a mitzvah to take care of one’s body, and to ensure that one is strong for the service of Hashem (see also Mishnah Berurah 155:11, who cites this).
For deeper meaning of the matter, see the Maharal, in his Chiddushei Agados. See also Yaaros Devash (1:6), who explains that Chazal mean to teach that one should not search for pleasures, but make one’s custom to eat bread and water.
Therefore, although it is good practice to eat breakfast, there is no obligation to do so, and everything depends on personal circumstances. If you will feel better without eating, you should not eat.
Additionally, there is no obligation to eat specifically bread for breakfast, and something satisfying and healthy is fine as an alternative. I have heard that somebody did some research into the matter, and found that there are specific health benefits of eating bread for breakfast (see Rachel Yahalom, Livriut [Heb.]), but I am not familiar with the matter.