The opening hours and the self-service are clear indicators that Iden is not meant to be the perfect restaurant for a romantic dinner. But for lunch it is an attractive option in Stuttgart.
You take the food from a buffet. There are several dishes like risotto or potatoes au gratin and sides like boiled potatoes or pumpkin. You can choose freely, everything is weighted and costs the same (a bit more then 2 Euro per 100g in November 2014). Additional there are a soup, some deserts, and cakes. All dishes are labled with the ingredients (in German) and there are some vegan options. Depending on your appetite, you can eat for 8 to 16 Euros.
The food is tasty and does not taste like cafeteria food. It was not as warm as a dish served right from the kitchen, but it was ok.
Cons: more cafeteria then restaurant