In Jainism, a short fast (often called an upvas or vrata) means abstaining from food for a part of the day or for a short period, as a disciplined practice to purify the mind and body.

Common form of a short fast:

• Eat or drink only to a limited extent, or stop eating after a certain time (for example, from sunrise to sunset) and resume later.
• Often involves avoiding certain foods (especially root vegetables) and might restrict grains or heavy foods, depending on one’s customary practice.
• Some people limit themselves to very light foods (like fruits or milk) or even take only water for a portion of the day.

Differences between Digambar and Shwetambar traditions:

• Digambar communities tend to be stricter in some cases, with variations in whether water is allowed and how long the fasting window lasts.
• Shwetambar communities usually allow more flexible guidelines for a short fast, again with regional or family variations.

Key idea:

• The purpose is self-control, humility, and focus on spiritual practice rather than dietary rules, so the exact form can vary by tradition and personal vow.

If you’d like, I can explain a specific short fast from either Digambar or Shwetambar tradition, or describe the typical rules for a particular festival day.