To what extent has the decline in desserts contributed to malnutrition?

[ah]

If you do a lot of baking, you'll know that almost every dessert contains sizable quantities of dairy and eggs.
As such I consider homemade desserts to be healthy due to the nutrients these ingredients provide, particular fat soluble vitamins, in combination with carbohydrates.
Everyone here also knows that desserts today replace butter with vegetable oil and eggs with other binders such as gums. These "replacements" are devoid of nutrients.
Clearly the consumption of "real" desserts has declined, but to what extent historically did desserts act as important supplemental source of nutriment?
Im curious what the average dessert consumption was a century ago versus today. Was it enough that it was an important source of nutrients? and is the lack of nutrients in modern desserts (as well as the malignment of desserts as "unhealthy") contributing to widespread undernourishment to a significant extent (say, 20% of daily fat soluble vitamin intake)?
I believe so.