As a chef at a resort, I am often asked to provide special requests for people who have medical issues, such as allergies, celiac, diabetes, etc. I can pretty much make people happy with some sort of alternative. I have no problem with this, and consider part of it customer service. Sometimes people just plain old don't like the idea of what I've put together, and ask for a substitution. Most of the times I can do it for free, sometimes, when a guest wants double asparagus instead of potato chips with a hamburger, I have to charge a little extra. I try to accomodate everyone.
I draw the line at providing nutritional information for guests. Gauging your food intake is your responsibility. It is mostly common sense. If you must know your calorie counts, there are several good nutrition manuals available in most libraries and bookstores and some computer programs which will help you learn how to estimate what is on your plate.
I personally have tried to add more healthy and vegetarian friendly items to my menus in the past few years. I always tell guests the truth when they ask how much a steak weighs, what is fresh, what is frozen, what is organic, etc...
If you want bacon and eggs for breakfast once or twice a week for a treat, great. If you eat bacon and eggs for breakfast seven days a week, lead a sedentary lifestyle, and don't drink enough water, that is your fault when you get sick.
If you eat fast food everyday, and you gain weight or get sick, don't blame the restaurant for not telling you how many calories are in something. You should be able to figure out that 7 cheeseburgers and fries a week is not good for you.
Restaurants are there to serve you. We want you to have a good time when you are with us dining. Most will accomodate your requests. Know what you want, and ask for it clearly to get what you want. ( I have a very regular guest who won't eat salt, sauce, seasonings of any kind, and wants his vegetables overcooked, his meat overcooked and untrimmed--and I do it for him--that is why he is a frequent guest.)
Be prepared to wait a little extra time or pay a little more to get what you want if it is not on the menu. Above all, be nice when you ask for something special. It works like a charm-e.g. ("If there is any bleu cheese on my salad when it comes, I'm sending it back and I won't pay for it" does not work as well as "Please make my salad without bleu cheese", or even "no bleu cheese, please".
If you think you have overeaten, you probably have. Ultimately, restaurants usually do what you ask. There is always a to-go box to make last night's dinner today's lunch.
I have given my opinion. If I have offended you, I am sorry, but these are my beliefs and how I guide my successful business. If the law ends up requiring me to post nutritional information on my menus, I will comply with the law.