Actually, for "fast food," I don't find Subway salads to be half bad.
They're definitely not "frankenfood" as they are created right in front of you after you choose the ingredients you want. My local Subways have lettuce, green bell peppers, red onions, tomatoes, black olives, jalapenos, pickles, and banana peppers available. Except for the last three items (which are pickled) the vegetables are all fresh.
Granted meat and cheese options at Subway tend to be a bit more "processed" but I don't consider roast beef, roasted turkey breast, chicken breast, tuna, bacon, ham, cheddar cheese, provolone cheese or parmesan to be "frankenfoods." Salami and pepperoni may qualify
...but I'll admit to still eating both on occasion! That just leave the dressing and I usually opt for either Ranch dressing or a mixture of mayo and olive oil blend. I'm not sure the salads I make from scratch at home are measurably "lower carb" or "healthier."
Typically, I only wind up at fast food franchises when traveling with other people who don't eat low-carb and who NEED to eat on a regular schedule. In such situations, if there is a Subway handy, I tend to vote for it over most other options.
I think overall Subway has options that are healthier than "a bag of nuts" and definitely healthier than a "no-carb bar." Actually, I've never yet found a true no-carb bar for sale anywhere and would love to know what brand you buy Bob-a-rama. Around here, we can get all kinds of high-protein bars (with way more carbs than I'd ever consume in a single sitting) and lost of supposedly low-carb bars made with so many sugar alcohols they might as well be CANDY the way they set off my sweet-tooth cravings! I have yet to see a bar with less than 20g of carbs and no (or very few) sugar alcohols.