In Jain tradition, during Chaturmas and especially during fasting or vrata, the foods generally avoided are those that increase violence, fermentation, or harm to living beings.

Commonly not eaten:

• Root vegetables: potato, onion, garlic, carrot, beetroot, radish, turnip, ginger, turmeric, etc.
• Green leafy vegetables and vegetables with many tiny living beings, depending on the vow taken.
• Fermented foods: idli batter, dosa batter, dhokla batter if fermented, curd kept too long, pickles in some observances.
• Honey
• Alcohol and all intoxicants
• Non-vegetarian food
• Food after sunset, in many Jain observances
• Stale, spoiled, or reheated food
• Water and food with many undetectable living beings, as far as practical observance allows
• In some fasting vows, even milk, curd, fruits, grains, and cooked food are avoided completely, depending on the type of fast

Important:

• The exact rules depend on which vow is being observed:

• Digambar and Shwetambar traditions may have some differences in practice.

If you are observing a specific Jain fast, the food rules become stricter according to that vow.