Intermittent Fasting proponents (Mark P Mattson, Andrew Huberman,...) believe no breakfast is the best breakfast.

Huberman recommends having coffee or tea for caffeine about 90 minutes to two hours after waking up.

I was on high complex carb (steal cut oats with soy-milk) for many years and I was happy.

But now I am firmly in intermittent fasting camp and do not eat before 12pm. I do have coffee or tea in the morning. I am happier on this new routine and definitely more alert!