When eating out, make sure to let the waiter/waitress know what your allergies are. You will find that most people aren't immediately aware that dairy means milk, butter, yoghurt and cheese, and that it may be in other ingredients as well, so you may have to explain in detail, and ask them to check with the chef if they're not sure.
If you have a serious allergy, it may be best to avoid eating out altogether - dairy and eggs work their way into so many foods, and it's difficult to be absolutely sure that your message has reached the kitchen and that the chef has checked every ingredient for dairy.
You will find that it's easier to avoid dairy and eggs in some types of restaurants than others:
- Italian and French foods often contain cheese and cream, and sauces often start with butter.
- Many Indian dishes contain yoghurt (often hidden in a marinade), and curries are traditionally cooked in clarified butter (ghee), although many restaurants use oil instead.
- Pub meals and bar food often contain butter and cheese.
- Spanish food, and certain varieties of South American food are often a good choice, as many such dishes don't involve any dairy or eggs. I was pleasantly surprised to see no dairy or eggs in any of these ceviche recipes, and there are a whole host of other South American and Spanish dishes that use similar non-dairy ingredients.
- Oriental food such as Chinese, Japanese, and Thai are usually pretty good options - many oriental people are lactose intolerant so dairy is rarely a part of traditional Oriental dishes. The main things to watch out for are eggs and battered things (battered foods often contain milk).