Restaurants serving foods other than traditional German foods

Where can I go to eat in restaurants offering other types of foods?

Anywhere and everywhere. German food has become difficult to find in Germany IME, which has perplexed and disappointed me to a certain degree. Same answer to your grocery question.

The world, and the cities in it, have become cosmopolitan with regard to food, music, art, clothing and other things.
You can now find almost any type of cuisine in both large and smaller German cities. And, yes, they even have vegetarian restaurants in what once was meat-and-potatoes Germany.

Where can I go to eat in restaurants offering other types of foods, ( salads w grilled chicken or salmon or shrimp or steak).

As noted above- just about anywhere. This is like asking where you can find Italian or Chinese food in the US. Oh, and you can find those even in small towns, too. My little Bavarian village had Italian, Greek, Mexican and Chinese, in addition to traditional Bavarian.

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Where can I shop in large German cities for fruits or other foods?

I would suggest a grocery store, supermarket, or food market.

Most mid-level restaurants, even the “traditional” ones, will offer a “Fitness Teller” ( healthy plate) with a grilled chicken breast or other protein, and salad. Or just go to an Italian restaurant——they are all over.

Where can I shop in large German cities for fruits or other foods?

In every supermarket, e. g. Rewe, Edeka, Lidl, Aldi and others. Some of them are called discounters but a recent price testing based on food basics showed that there was not 1 Cent difference.

In most German food restaurants you will also find salad variations. You will also find a lot of grill restaurants and steak houses, some of them as a chain with branches, e. g. Block House.

As fast food I recommend to try a Döner Kebap whcih is a quarter round bread with choice of meat and salad and a dressing. If you prefer a salad look at dean&david branches.

Worth a try are also various sausages from a grill, e. g. Thüringer Rostbratwurst.

My wife and I have a great meal at an Indian restaurant at least once per trip. They normally have vegetarian dishes as well as beef, lamb, chicken. Many years ago, before my first visit to Germany, I was worried I wouldn't like the food. I was very, very wrong.

Salmon, chicken, and steak are all traditional German foods. But you can find pretty much anything in the major cities. Indian, Asian, British, American, Moroccan, Japanese, Chinese, Turkish, etc. The salads are a bit different. Ranch is not a thing. Pickled foods are a bit more common, as are veggies you probably don't encounter as much (cabbage, beets, turnips, shallots, etc). I usually get my produce at the open air markets, and every town has one. Usually on Saturdays in the bigger places, weekdays everywhere.

The restaurants have their menu's posted outside, so you can tell what they have before entering.

There is no across the board "Traditional German" food. Each region has its' own, though you can often buy certain menu items in other regions. Like Käse Spätzle, which is basically German mac and cheese, but way better. Frankfurt Grüne Sosse, somewhat similar to sour cream and chives on potatoes, but with more herbs and a hard boiled egg. Also served on a schnitzel if you like, making it a Frankfurt Schnitzel, but more commonly served on potatoes. Mushroom dishes are popular, pumpkin ravioli is popular too. Look on the vegetarian / vegan options in pretty much every menu and you may be surprised at what the cook has created. One chain, Hans im Gluck, has at least 6 vegetarian burgers and 6 vegan burgers, as well as regular burgers. Sweet potato fries can be found in many restaurants. Flammkuche is widely available across Germany, though it comes from the Alsace region. My favorite has mushrooms, spinach and mango on it.

That said, Frankfurt has restaurants from around 80 nationalities here, so you can have your choice. Lots of African, Indian, Middle Eastern, Asian, Israeli, moving on towards niche restaurants serving Peruvian, Cuban, or Mongolian.

All that I will add to these great responses is that you may find non-German menus less common in smaller towns and villages or if you stay at a small country inn or guesthouse.