Maybe you should try something like this to prevent people eating your food:
As for me, I haven't had experience of people eating my food, coz I usually eat as soon as possible. I'm not the type that like to keep food too long.
In my house, we have a rule that whoever leave their food in the fridge exceeding more than 3 days, that food will be free for the taking. This is b'coz our fridge used to have too many uneaten food in it. Some of the food have been in there nearly a year.