Underground, I can't beat pepperamis. I first started taking them underground when I was not allowed sugar by my dentist due to dental work. I found they work far better than chocolate bars or the traditional snack foods, for the following reasons.
1) Once eaten it staves off hunger panes for a good few hours as its a slow release energy source.
2) They come in foil sealed packets, which unlike most chocolate bars etc rarely burst and the contents are not turned to mush.
3) They are not very thick so don't get in the way on tight squeezes, easily fit in my under-suit pocket, without causing me any problems.
4) They are not as bad for your teeth, except, I feel I need to bring a tooth pick along sometimes. Oh well hopelessly trying to dislodge small bits of meat with my tongue gives me something to do while waiting to go up pitches.