People eat pretty much the same things that you eat at home in Australia, such as potatoes, chicken, beef, ice cream, etc. All the good stuff. There is a chef on station who cooks most of the meals. As a result, everyone gets a good variety of meals while living on station. Often there will be a theme night, such as an Indian banquet. On these occasions, not only is the food prepared according to the theme, but many expeditioners will also come in an appropriate costume.
One point to remember though is that it all food is delivered during the summer resupply. In order for it to last for an entire year, much of the food is frozen, or tinned. Each ship into station will typically deliver “fresh” fruit and vegetables—but these have already been on a ship for several weeks. We also have hydroponics in hot house conditions to grow a few fresh vegetables like lettuce and tomatoes. These are used to augment the winter food supplies.
Not all food that is eaten on station can be taken out into the field. The main example of this is poultry (chicken, eggs, turkey etc). This is to prevent the spread of diseases to Antarctic wildlife, particularly penguins. Recently antibodies to Infectious Bursal Disease Virus (a disease of domestic poultry), were found in penguins, indicating they had previously been exposed to this disease.