Answer

In Jain Dharma, the difference is mainly about what is avoided and when:

• Tivihar Upvas: Complete fasting from food, but generally boiled water may be taken during permitted daytime hours.
• Panahar Upvas: A stricter form where one generally avoids food and water for the full fasting period.

Explanation

Tivihar means avoiding three types of intake:

• Food
• Drinks other than water
• Other edible items

So in Tivihar Upvas, a person does not eat food, but may drink properly prepared Jain boiled water within the allowed time, according to tradition and personal capacity.

Panahar Upvas is usually understood as a more intense fast where even water is not taken. In many communities, this is similar to what is also called Chauvihar Upvas, where both food and water are avoided.

Spiritual Understanding

Both are forms of tapasya, meant to reduce attachment to the body and senses, practice self-control, and support purification of karma.

The greater importance is not only the physical fast, but also:

• Maintaining peaceful thoughts
• Avoiding anger, pride, deceit, and greed
• Doing samayik, pratikraman, swadhyay, mantra, and bhavna
• Practicing humility and awareness

Takeaway

Tivihar Upvas allows boiled water during permitted hours, while Panahar Upvas is stricter and generally avoids even water. The best fast is the one done with purity, discipline, and inner spiritual awareness.