I also grew up in Germany. Quark was an everyday item on our breakfast table. The kind we bought had freshly cut chives in them - DELICIOUS! (If you make quark - try adding chives). We would spread it on fresh broetchen (rolls - plain, sesame, poppy seed, with oats, etc) or on the hearty dark breads - pumpernickle, farmers bread (Bauernbrot), 6-grain bread (Sechskorn Brot), etc. I believe that these breads are quite low in fat - except for the ones that have sunflower seeds in them (Sonnenblumen Koerner). I would recommend to go to a bakery and maybe buy one to try.
As for low fat foods in Germany, good luck. Germans use a lot of half and half in their sauces, butter, and lard. They still drink whole milk in many places!! If you order a salad, it comes with their dressing on it .... A lot of times the salad soakes in the dressing - you don't have the opportunity to order it on the side. I would stick with Italian, probably - plain noodles with a maranara sauce - or maybe an italian salad - with no sauce. Also remember that in Germany, big salads usually come with slices of ham and cheese in them .... Also avoid the potato pancakes - they are dripping in fat!!!