I do typically carry some snacks with me - those little packs of almonds are handy! I also get the bags of dried blueberries or cherries from Costco, and break them down into little snack packs.
I haven't found a restaurant yet (real restaurant - not fast food
)where I haven't been able to enjoy a great meal - like others, I'm not afraid to ask for substitutions (green beans for mashed potatoes, for example, or a salad instead of fries). I usually start with finding my protein, which is usually salmon or another kind of fish (I love trying fish in restaurants!), and then go from there - a quick look at other items on the menu will give you an idea of what is reasonable to ask for as a substitution.