Question: Should I force myself to eat when I have a cold or flu, even if I don't feel like it?
Answer: Oftentimes when we get a cold or the flu, we lose our appetites, and that's very, very common. It's not important to force feed yourself in order to keep up with the cold. However, it is important to stay hydrated. What I'd recommend is actually drinking as many liquids as possible. Oftentimes warm liquids are more soothing that cold liquids.
So a lot of people will advocate drinking soup or tea to try to soothe your sore throat or any other symptoms that you're having. If you can eat that's wonderful because good nutrition will definitely help you get better faster as well. But at least stay hydrated.