I flew a lot on many different airlines, and as a rule I never eat in a plane (yes even on 15 hour flights). Thus it was the opposite problem, but I can still answer based on experience :)
In my experience this largely depends on the airline. Thus you need to ask a flight attendant once you board: "if I'm asleep, will you wake me up when serving dinner?" If they do not, ask "what shall I do to ensure you would?"
European airlines (except low cost) tend to wake up everyone (Lufthansa even forces you to bring your seat upright even if you don't eat). So if you are flying with one, you will not miss your food. If you want want to be left alone, you have to tell a flight attendant, but in my experience they ignore this and will wake you up anyway.
American airlines, and low cost airlines all over the world tend not to wake passengers who are sleeping at all, unless you're obviously in distress. However they usually will reserve a meal for you, and would be glad to serve you once you're up.
Asian airlines also tend to not wake people up (with strange exception of China Southern), and some - Korean Air and another one - even give you the following stickers, which you are supposed to put on the headrest:
if you do this, they will respect the choice. If you do not, they seem to be trying to guess how deep is your sleep, by verbally asking if you want to eat. If you do not respond, they leave you alone. They will always have an extra meal anyway.
Also, as others mentioned, the airline will almost always have an extra meal for you. But to ensure this, you can order a special meal at check-in.