Here's a problem the wife and I have run into.
We've recently begun to lower our carb intake. It changes what we can / cannot eat. It pretty much means no breads / sweets. This makes having a hotdog or a burger on the fly tough (while you can get them without buns, things get messy fast). Most snacks have many carbs in them so we have to keep away.
Most of what I listed in my prior post is off limits. So now I keep just water and generally nuts of some kind on hand.