I agree, it’s a trick question because no food is healthy by itself, foods are only healthy as part of a whole. And as long as your foods usually fit with the basic standard advice, then you’re eating healthy foods.

If you have cheese as a large component of almost every meal, then you’re deviating a lot from the basic advice, so it’s not healthy. If you have a bit of cheese on your breakfast of eggs and toast a couple times per week, then it’s healthy.