Dried fruits and nuts, preferably organic - keep us healthy on the road

'Meal replacement', 'energy', 'protein' bars - sometimes.
These are convenient to carry, but most taste horribly
Some of them "can have" laxative effect - so hardly a travel-snack
Example: "Protein Plus" bars state so on labels and taste like medicine.

There is one advantage to food-replacement bars - oftentimes they can be purchased for free in US supermarkets and drug/pharmacies. Some of the participating brands: Kashi, MetRX, Pure Protein, Zone.
If anyone transiting SFO wants to try some - let me know - I'll be glad to supply you with a case or two

Someone else mentioned Cliff brand: ok, add me to the club, so far I like them.
Speaking of Cliff, they make something called "fruit rolls" - those are delish, BUT terribly sour, must be due to excessive use of vit. C. Healthy though, definetely good for the immune system on the go.