In Jainism, nighttime eating (rātrī bhojan) is generally avoided because it can hinder spiritual disciplines and purity in several ways:

• Digestion and energy: At night the body’s digestion is slower. Eating then can disturb sleep and create heaviness (śīla) in the body, which makes it harder to practice keval jnāna (omniscience) and meditation with alertness.

• Sattva and discipline: Night meals tend to increase tamas (inertia) and passions (kāma, kāla, and rāga), which obstruct equanimity and self-control valued in Jain practice.

• Karmic impact: In Jain thought, actions that create excessive bodily sensation or attachment can bind karma. Eating late can generate more attachment to food and comfort, hindering the shedding of karmic bonds.

• Vows and routine: For many Jain ascetics and lay followers aiming for self-restraint, avoiding night eating supports regular discipline, simpler living, and better adherence to vows like non-violence (ahiṁsā) and celibacy (brahmacharya) in daily life.

Note: There are differences in Digambar and Śvetambar texts regarding exact timings and prescriptions, but the overarching principle is to minimize activities that disturb mental clarity, self-control, and spiritual progress.

If you’d like, I can share a concise Digambar vs. Śvetambar note on this topic and point you to authentic Jain sources for deeper study.