Most food that is in restaurants is pretty unhealthy because there are no negatives (short run) for them to make the food unhealthy. I always assume that by making food more unhealthy it directly makes it more tasty (not completely, but most people would agree).
Restaurants do not need to post their nutritional information (although, I wish they did). So what benefits would they have to make something healthier? Very little, because their customers will never know.