Table service should be easy cheesy, and in the nicer places the staff and chef will even assist.

Counter service will be tougher, but they have options like carrots or grapes instead of fries, so that depends on what type of low-carb diet your on, how hardcore your doing it, and if your in induction phase.

As for desserts, another tough one, and again probably the closest you will get is fruit, which I know has carbs...

Like being in a foreign country, sometimes it is easier to modify our diets to our surroundings than the alternatives.