The Viennese wrote the book on these. This is not a city for calorie counters, but if you follow that trend remember that Vienna makes its own rules. Chocolate has no calories in Vienna. While Sahne is loaded with calories, Schlagobers is totally calorie-free and can be added to everything from coffee to cake, to Paprika Chicken and to every kind of pasta. If Schlagobers isn't used in a dish, it's probably because the cook has used loads of butter instead.
Austrian butter has no calories either.
The result of all this non-calorie food is that Austrians tend to avoid the twiggy look quite successfully. They are also very friendly. Don't believe those cynics that say it's because they are too overweight to either run or fight. Of the Viennese coffeehouses and cake shops, the names that come to mind are Demel, Heiner, Sluka, Lehmann, to name just the tip of the iceberg. Sadly, I have to report that on my last foray to Vienna, I went into Sacher for a piece of their famous cake and found it dry and not up to the standard expected.