I eat out quite often and still have managed to keep the weight coming off week after week. Here is what do;
Salads with protein (fish or chicken) and allowed veggies I ask to mix in mushrooms, tomato (my coach let's me have), red onion, whatever . . . and then I just get olive oil and white vinegar on the side and add my sea salt (I bring) and pepper.
or. . .
I order a meat entree of chicken, beef or fish and asked for steamed veggies. I tell people absolutely no dairy (they think I'm lactose intolerant then and are really careful to make sure no dairy in anything or on the meat).
Bring your own salt!
It seems to do the trick and I get to eat out.
Hope it helps!