As do all other bees, including the solitary, subsocial, and eusocial species, adult honey bees eat pollen, nectar, and occasionally the honeydew produced by aphids and other species of Homoptera.
They store both pollen and nectar, the latter in the form of honey, in their nests for future use. Pollen is their source of proteins, fats, vitamins, and minerals, all of which are essential for reproduction and growth.
Nectar is largely a source of the sugars that provide the energy bees require.