Actually, given that it seems insurance will pay for visits to actual nutritionists and dietitians as well as partial payment for gym memberships (presumably dependent upon insurance plan surely), I'm not particularly surprised of a lack.
Check at your local hospitals to find out if they have weight group meetings - they do have such in Basel but the language apparently is German, perhaps Zürich may be more likely to have an English-speaking group sponsored at the hospital though.
I know it's not going to give you the face to face contact, but what about weightwatchers online? They give you personalised feedback based on your progress, tools for tracking, recipes and tips and everything. [Obviously it costs money, but then so does going to a WW meeting]