No. They're completely different things. Genes are a cookbook. Gene expression ("activity levels") is cooking. You don't need to rewrite the cookbook every time you want to cook something different, you just pick a different recipe from the book. Gene expression changes all the time. That's how you can have different types of cells even though they all share the same DNA. And that's how your cells can adapt to changing conditions. Including changing your diet. Or spending a year in space.