If you want to stick with your high-carb fueling plan, my advice is to just start riding and eat on the bike. This will limit your speed a bit as you'll need some blood flow to digest your food, but this should be doable.
If you are open to a different perspective...
The problem you are having is because you are a good carb burner and a poor fat burner. That's because you are always exercising in a situation where there is lots of available glucose and that does not train up the fat-burning part of the aerobic system. You are therefore dependent on your glycogen reserves and regular carb intake, and in your current situation that's not sufficient.
The best way to become a good fat burner is to taper the amount that you eat on your slow rides, eventually tapering down to doing the ride fasted. If you do that *and* you ride slowly enough - zone 2 or lower - then you will build up your fat-burning ability and your problem will go away.
The added benefit of this is that zone 2 training is really useful on its own.
If you want the really long version of this advice, see here.
There is a book on low carb endurance diets:
I personally dont follow the approach in this book.