On Aatham (8th tithi) and Chaudas (14th tithi), lilotri / green leafy vegetables (saag, hari bhaji) are avoided because these two tithis are specially kept for extra ahimsa and saiyam.

In simple points:

1. More jeev (life‑forms) in greens

- Leafy vegetables, coriander, methi, palak, etc. have many tiny insects, eggs and moisture. - Cutting, washing and cooking them usually involves more himsa than using dry grains or pulses. - So, on days of stricter discipline, Jains avoid this whole group (called lilotri tyag).

1. Aatham & Chaudas are “pakshi saiyam” days

- Every fortnight, Aatham and Chaudas are taken as special dharmic days: upvaas, ayambil, more pratikraman, svadhyay, etc. ( jainknowledge.com) - To match this higher spiritual mood, food is made simpler and less violent, so green veggies and often some other items are given up.

1. Tradition of tithi‑maryada

- In many Shwetambar families: - 1‑tithi = only Chaudas; - 2‑tithi = Aatham + Chaudas; - 3, 4, 5‑tithi add more days like Poonam, Amas, Choth. ( jainknowledge.com) - In these niyams, the basic rule is: “No greens (lilotri) on these tithis.” - Digambar families also keep special tithis with similar idea: less variety, less taste, less himsa; lists can change by acharya‑maryada.

1. Link with pratikraman and repentance

- Especially on Chaudas, Jains focus on introspection and repentance (pratikraman). Food discipline supports this inner cleaning. ( jainknowledge.com)

So, lilotri tyag on Aatham and Chaudas is mainly to:

• reduce subtle violence in food,
• keep the diet very simple,
• support tapas, pratikraman and a calm, restrained mind on these important tithis.

You can read a simple explanation of tithis and Aatham/Chaudas practice here