Why can't we smell and eat if we have cold?

We can't able to smell when we got cold. Normally, our nose has specialized olfactory receptors covered in a thin layer of mucus. In normal conditions, the odorants diffuse through the mucus and reach the receptors and activate them and allows us to smell. However, when we get cold, our nose produces excess mucus and hence the odorants are unable to reach the receptors and hence we feel difficult to smell during cold.

                          When we eat, the specialized gustatory receptor present in the tongue tell us whether the food is sweet or salty. The odorants present in the food travel to the olfactory receptor from mouth to nose. The combination of information from the gustatory and olfactory receptors give us the sense of overall flavor. As we have cold, the olfactory receptors cannot detect the complete smell. And hence, we do not get a overall flavor of the food.