My favorite sight has been the mother-daughter pair I saw on the Bosporous ferry. They were hugging each other on the bench and had virtually the same profile features, yet the mother carried full traditional dress and the daughter wore a mini-skirt and was otherwise dressed comparably. They loved each other dearly.
How you interpret these women is central to how you view Istanbul. One intuition is that they are quite alike, another is that they are quite different.
And the food? You can eat the traditional dishes, in simpler settings, or you can pay extra to eat them — slightly modified — in more gussied up surroundings. The key to eating well here is to go simple and to look for the best and purest versions of straightforward dishes. World class raw ingredients are at your disposal, if only you don't let anyone ruin them.
It's not hard to find the good stuff. Thousands of street restaurants offer seafood (the fried small smelts are my favorite, then the sea bream or "levrek"), eggplants, fava beans, doner kebab, fried mussels, salads with cheese and tomatoes, lamb brains, fried and baked potatoes, Turkish ravioli (harder to find), spicy kabob with sumac, and other delicacies. It is common for the small restaurants to specialize, an indication of quality. A meal in these places, with one small portion, will cost six to ten dollars but you can (and should) order more. Turkish sweets are the dessert and I prefer something with pistachio.
The rest is a sideshow. Avoid all restaurants near the main sights or near clusters of tourist hotels. Avoid most of the places — even Turkish ones — on the main thoroughfares. Look for the neighborhood side streets with clusters of these small restaurants, just off the larger roads. If you order small dishes, you can visit two or three restaurants in one meal, no problem.
My favorite small Istanbul restaurants have been the soup houses, especially the tripe soup (NB: you don't have to like most tripe dishes to enjoy these creations). You ladle in some liquid garlic sauce, paprika, a bit of chili pepper, and a green herb of some kind. Some of these places are open for breakfast.
Unless you've bled this city dry and sampled all the major dishes (which would take a long time), the return to going upscale, or seeking innovation, is not overwhelming. What happens is that you're either paying higher prices to be in the company of attractive Turkish women or to impress attractive Turkish women who are already in your company. Not that there's anything wrong with that, but the basic market model here is segregation of restaurant type. If it's food you're after, don't pay more for the culinary twists. The food will remain recognizably Mediterranean but it won't be the classic treatment you are looking for and which to you is still original on the fifth day of your trip.
If your restaurant has a good number of attractive Turkish women in it, perhaps you made a food mistake. Or should I say a money mistake? Or what kind of mistake? The cuisine still will be good.
The good here is very good and the best isn't that much better.