Good options for bites to eat on the run include small cut-up pieces of cheese, cheese and meat roll-ups (either plain or rolled up in a leaf of lettuce, roast beef from supermarket delis has never caused me any problems -- I don't think it has added sugars the way ham often does), hard boiled eggs, nuts (once you are past induction, but watch the quantitities), and celery sticks with peanut butter inside (again, past induction). For emergencies, you might want to keep an Atkins bar in your purse. I can't stand them, but some people like them and they are easily portable. I have a friend who travels about half the year for work and is following Atkins. She never goes anywhere without a couple of emergency bars.

Once you get away from the mindset that sandwiches are the only thing you can eat on the run, it's easy to find alternatives.