When I was in college and lived with, at one point it was 8 girls, we always bought our own food. I think we might have split things up once or twice, but realized that splitting groceries wasn't going to work out for us because of different schedules and eating habits. Since I moved in the with B.F., I haven't exactly lost weight either. The majority of the reason is because I've been lazy and haven't been to the gym or outside running consistently, however, we don't like the same food.
The B.F. is more of a meat, potatoes and pasta kind of guy. I never grew up eating pasta in every meal -- I'm not Italian, he is. As I got older, my parents became more interested in eating healthy so everything was grilled -- vegetables, bread, steak, pork chops and chicken. Yes, even bread. My dad found this recipe by Emeril where you drizzle olive oil and add cracked pepper and salt and grill it -- it's fantastic. What I'm basically saying in a very long sentence is that we eat completely different. I want grilled chicken with a side of asparagus and roasted red skin potatoes. The B.F.'s is any kind of chicken or steak with pasta. Lots and lots of white, starchy and unhealthy pasta. I eat, 99% of the time, whole wheat pasta and bread. On occasion, when we are out at a restaurant, I'll eat a piece or two of white, starchy substance -- but most of the time I say "white bread causes cancer" to refrain myself from eating it.
We definitely differ on dessert though. I will eat less at dinner so I can order dessert or go get ice cream. He isn't that keen on dessert, but I'm a fanatic and always want to try new things when I'm out or try a new flavor of ice cream. Or, I'll make brownies or cookies so I can eat the batter. (Maybe this is why I haven't lost weight?)
He is also a picky eater. He doesn't like tomatoes, salmon, tilapia, tuna (hates it), whole wheat products, cucumbers, zucchini and squash. His picky habits limit me because I sure as hell won't be able to eat food in a fast enough time to buy separate items, before the food goes bad.