I am travelling in economy class on an Emirates 777-300ER from Birmingham (BHX) to Kuala Lumpur (KUL) via Dubai (DXB) shortly. I would like to know what the meal choices and their general ingredients will be, as I am deciding between the low-calorie/low-cholesterol meal and the Hindu meal, which a colleague flying a short time later has selected.
Low-calorie, low-cholesterol and the whole low-series are special meals, which are served upon special requests. You do not usually find those with the normal choices. Some airlines in long hauls serve "light meals" as a standard choice, but I would not depend on that as airlines usually have cycles for services, this might be every 2 or 3 months or so. Airlines also (especially large ones) can not just put their menu online, as their menus are prepared by many contractors around the world and it will be so difficult to keep track of what exactly will be served in every single flight, usually the catering company provides the menu along with the meals prior to departures (out of personal experience as a cabin crew member).
Regarding choices, it is a rule of thumb for large international airlines to provide different choices of meals to satisfy all people, one dish from the origin country, one dish from the destination country and sometimes an international choice. So, if you are the type who does not like trying new options, you will usually find a choice familiar to you from home
Anyway, in some reservation printouts you will find the type of service, not the specific dishes. For example you might find "HLD", "HBR", etc. which means hot lunch/dinner or hot breakfast, etc.
Last thing, as mentioned by @downhand in a comment, special meals are usually bad and tasteless, stick with the standard menu unless you have some health issues or so.