There is a very old saying that you should feed a cold and starve a fever. While there is certainly no need to stuff yourself if you have a cold, it is generally recommended that you eat regular meals. Really, the best foods to eat are those that are healthy at other times: avoid high fat toods, limit your dairy intake as it can make catarrh worse, and get lots of fresh fruit and vegetables. Fibre, such as is found in granary bread, sweetcorn etc, is also good to build up strength and aid recovery. And do drink plenty of fluid - plain water is the main thing, though many people find that barley water is refreshing and may soothe a sore throat. There doesn't seem to be much evidence that the traditional whisky and hot water with lemon and honey will actually cure anything, sadly.

There are no miracle foods really - just healthy eating and common sense. You can find more ideas here.