There are many things in the food we eat.

I find that comments like " I only eat once a day" says to me the person is possibly lacking in many things.

For example... this came up on another post:
Glycine. This is an amino acid that is present in root veggies like beets. Glycine is necessary for many biochemical functions in the body. It provides a methyl group to methylation reactions. If you cannot synthesize it yourself, you suffer and depend on food sources.

Other important things in food are
choline (eggs)
methionine (animal protein)
sulfur containing amino acids
and there are more, but I am not going to search them
now, because of a time constraint.

So it is not just vitamins and minerals, which ARE important, but the other nutrients in foods we depend on.