Āhāra: 'nutriment', 'food', is used in the concrete sense as material food and as such it belongs to derived materiality see: khandha Summary I. In the figurative sense, as 'foundation' or sustaining condition, it is one of the 24 conditions paccaya and is used to denote 4 kinds of nutriment, which are material and mental: 1: material food kabalinkārāhāra, 2: sensorial and mental contact phassa, 3: mental intention mano-sañcetanā, 4: consciousness viññāna.
1: Material food feeds the 8-fold materiality having nutrient essence as its 8th factor i.e. the solid, liquid, heat, motion, color, odour, the tastable and nutrient essence; see: rūpa-kalāpa. 2: Sensorial and mental contact is a condition for the 3 kinds of feeling pleasant, painful and indifferent; see: paticcasamuppāda 6. 3: Mental intention = kamma feeds rebirth; see: paticca-samuppāda 2. 4: Consciousness feeds mind and materiality, nāma-rūpa at the moment of conception Vis.M XI.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.