I'm not far from Mannheim and Heidelberg - Steffi Graf's home town, Bruehl, down in the south-west, in Baden-Wuerttemberg. My husband's retired USAF and works for the US Army as a contractor, hence being in this part of Germany. Sounds as though AAFES and the NAAFI have a lot in common! That said, I can get 93% lean mince, and other really lean cuts of beef, and there's a couple of ranges of fat free yoghurts (including the Chobani Greek ff yoghurts that are just heavenly!) that I can use.
Magerquark and 0.2% fat Speisequark are very useful standbys - think of them as unsweetened fromage frais and use them in sweet or savoury dishes. Knorr and Maggi do a good range of seasoning mixes and some dried packaged soups and pasta dishes, if memory serves, though I've never done a comparison against UK brands. I cook mainly from scratch and always have done since I started cooking as a kid. I don't routinely do a grocery shop locally as the Commissary is so much cheaper, and also carries quite a few of the local ranges (I can buy my Quark there, for example). Aldi, Lidl, Real and Edeka are the only stores I really know, and I usually use Real or Edeka if I'm short on something and can't be bothered driving the five miles or so in to Schwetzingen to the Commissary.
Should be off to Florida some time in the next few months, though, which is rather exciting.