"Thanks, but they're not kosher."
And since smell is a huge part of enjoying a good meal, troposmia can mess with the way food tastes, too. Outside of the broad flavors like sweet or sour, more delicate distinctions are processed through our nose -- we "taste" garlic, citrus, and the like by smelling them. Keeping a straight face while drinking terrible soup at your mother-in-law's is challenging enough. Now imagine it tastes exactly like dog balls.
Scientists are unsure whether the issues arise in the nose or the brain, as the syndrome has abated slightly with treatment on each area in different patients. It can be caused by infections, or head trauma, or who the hell knows what else. Let that be a lesson to you to always stop and smell the roses, in case one day they start to have a whiff of shit.