I carry a small bag of Brazil nuts in my bag, just in case.
When I've needed to be pounding the pavements for several hours, and I know it's going to be cold and wet, I take a few slices of Cheddar wrapped in clingfilm. Very comforting when you are cold, wet and tired.
Carrying something around helps to avoid the 'Pret effect'.
But as catinahat said, with LCHF there's not this 'I must have something to eat and now!' that you get with a high-carb diet.
Edit: Nuts should be varied. Don't have too many Brazils, for instance.