Hopefully most of the tourist or better to say all of the travelers enjoy eating Iranian foods. There are a variety of restaurants with nice designs and atmosphere to experience energetic and crowded fast foods opposite calm and relaxed traditional atmosphere with a classic Iranian music. The taste variety is also considered in Iranian foods. The Iranian restaurants foods are mostly cooked with meat like chicken, veal, fish and lamb.
The pork is banned. The vegetarians can also order the raw and cooked vegetables in the hotels besides the outside restaurants. The variety and availability of vegetable foods are less than other types of foods.

travelindependent.info says:
Eating can be somewhat difficult in Iran. Restaurants are seldom geared to tourists and signs/menus are mainly in Farsi. Food isn't that bad, with plenty of rice, yogurt and salad. Fish isn't too common and most dishes contain meat. There are plenty of pizza, and kebab/burger places around, but none are likely to excite your taste buds.

You can buy any kinds of soft non-alcoholic drinks. There are Iranian-made drinks as well as international brands served in supermarkets, coffee shops and restaurant. People drink tap water. The newcomers would rather take the mineral water.