Nutrition on the road - What, How and Why?

The American 'peanut butter and jelly' (jam) sandwiches are harder to digest but might do the job. They will provide more sustained energy but shouldn't break the bank. Wash down with plenty of water.
Peanuts are rich in magnesium.

Wilko uses PB & honey. Use white bread - you don't want fibre. I tried 'em but prefer my techno 'food'.