Original reporting
Taste is mostly smell — pinch your nose closed and a slice of raw apple and a slice of raw onion become nearly indistinguishable, which is why food goes flat the week you have a cold.
When you lose your sense of taste during a cold, your taste buds aren't the problem—your nose is. Smell does most of the work your tongue gets credit for, which is why foods become indistinguishable textures rather than flavors.