Of course, I'm an avid traveller, but I am an equally avid foodie, and so is my friend, with whom I stayed for 2 winter weeks in Dec-Jan. Luckily Swiss food, even in winter, didn't disappoint. Switzerland is a great country for foodies, as their regulations tend to encourage freshness, absence of additives, and locally grown produce. In fact, our trip turned out to be more gastronomic than globetrotter!
As is the case in many European countries, Swiss cheeses were abundant, varied, and extremely delicious. What we in the states generically refer to as "Swiss cheese" comes in as many as 10, even 15, varieties at any local cheese counter. Fortunately, most vendors are willing to give you a sample of their wares, so long as you reciprocate the favor with a purchase. The Swiss are famous for their cheese dishes, such as raclette (cheese melted under a broiler and then scraped off--you get your own personal numbered plate that they reuse!) and fondue, which comes in all different flavors. Both are served with bread, potatoes, pickles and onions. I must say I prefer the latter, and heartily recommend the "fines herbs" kind, if offered on the menu. Don't drink anything cold with your fondue, or all the cheese will congeal in your stomach and give you indigestion. Stick to alcohol, or hot tea or coffee in order to avoid this. Also: don't be afraid to order fondue more than once! Get it in several different restaurants, in several different cities--find your favorite! Everyone has his/her own unique recipe, and they're all bound to be tasty (how can you go wrong with melted cheese?)!
There are a few epicurean delights available in Switzerland that I do encourage you to try, if not for their inherent deliciousness then just to experience typical Swiss fare at its finest (and sometimes, weirdest):
Ovomaltine: kind of like Ovaltine in the States, but not as sweet, and more vitamin-y. It's an acquired taste that becomes addictive! There are also many other Ovomaltine flavored products (energy bars, cookies, etc), all of which are good but taste little like the original drink.
Marrons: chestnuts, prepared in every way imaginable, are prolific in Switzerland. You can't escape from them- they're in everything from ice cream to dinner entrées to yogurt. They're also delicious (and cheap) just plain and roasted, purchased from a street vendor. Even if you think you don't like chestnuts, try a candied one (marron glace') from a pastry shop.
Patisseries/chocolatiers: they're full of delicious baked goods and chocolate yumminess. Just go in, and point to whatever strikes your fancy. Try a petit-pate en croute, or a passion fruit-filled truffle.
Rivella: an unusual Swiss soft drink that is enriched with milk serum for protein. It comes in 3 flavors: regular, diet, and (my personal favorite) green tea. It tastes like a slightly medicinal lemonade-tea-soda, and is a great thirst-quencher if you're hungover.
Cheval: horse meat. It sounds off-putting, but it tastes just like beef. It's better for you since it has less fat, and higher protein. Try one of the many by-products, like cheval sausage.
Rabbit: something we have in the States although not as visibly. I braised mine with red wine and fresh chanterelles (wild mushrooms are also quite common and affordable there). Try a slice of lapin terrine, since almost any meat counter is bound to have several different flavors, with a crusty baguette.
Luxembourgi: these little macaroon cookies are quite possibly the tastiest thing you'll have in Switzerland, consisting of a fruit or cream filling sandwiched between two chewy cookies of the same flavor (try lemon, anise or the ubiquitous marron). They differ from region to region -try Sprungli in Zurich- but my favorite were from Laduree, in the French speaking part of the country. www.laduree.fr
Rosti is another typically Swiss dish, though overrated. It's basically glorified hash browns, and I didn't try any that were superior to hash browns or home fries you'd get stateside. If you're hell-bent on eating rosti, go ahead, but my suggestion is to skip it altogether and opt for the fondue!
Since Italy and Switzerland share a border, Italian fare is common and usually pretty good, if overpriced. If you're like me, however, you're a stickler for authenticity (read: Swiss food in Switzerland, and Italian food in Italy). If you're feeling like Italian, try specialties that are not as well-known to Americans, like tagliatelle with mascarpone and walnuts instead of linguine with red clam sauce. There are several grocery store chains, the major ones being Coop, Globus (high-end and rather too big for its britches), and Migros, a Swiss conglomerate. You should shop around, of course, but overall my pick is Coop, as it has a good selection and good prices. Swiss wine is somewhat more expensive than that in neighboring countries, but the local Fendant (a crisp white) is delicious and indispensable when paired with your fondue. In general, try to avoid foods that are not indigenous to the region, or international foods that are specialties in Europe; suffice it to say that the sushi in Geneva was pretty much the worst I've ever had (and among the most expensive). Stick with what the Swiss are good at--bread, cheese, produce, chocolate, and wine for example--and you should have a pleasant and rewarding epicurean experience in Switzerland.
Happy Eating!