Tin Pot
Guru
I do about 10miles, but get headaches that some on during the ride. It’s quite hard work at times as it’s very hilly near me...and I’m a beginner having only just got on a bike after 27years of no exercise....
A (small) bowl* of cereal or porridge, sometimes I prefer toast/peanut butter, should be fine.
If you eat as soon as you wake, then sort the bike and kit out, then perform the mornings ablutions, the food should have had time to settle.
*After many decades I’ve realised my portion was double or triple what I actually needed. A big bowl of cereal could make me uncomfortable on a hard ride.