Based on the verse “Lo tochlu al hadam,” in Vayikra, we learn that one should not eat before praying in the morning.
There is also the concept of Oneg Shabbat. Which basically means that you should be enjoying Shabbat and not be experiencing voluntary pain.
With that being the case, is there a difference between eating breakfast before a weekday Shachrit or a Shachrit of Shabbat? The Shabbat Schachrit in most places ends around 11 am and a person might get quite hungry by this time.
I am aware of custom to eat a snack followed by kiddush between Shachrit and Mussaf, but my question deals with specifically eating prior to Shachrit.