system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does macaroni and cheese lose so much flavor when refrigerated then reheated?
gpt
When you re-heat things in a microwave, water molecules are what absorb the microwaves and receive the energy. With things like cheese, that makes the water kind of separate out and makes the cheese more 'soggy and stringy' instead of 'foamy'. Texture changes taste.     
If you re-heat your Mac and cheese in an oven instead of a microwave, it will be much better.