Upvas in Jainism means observing a vrata (fasting vow) to purify the mind and body and reduce harm to living beings. It is a voluntary, disciplined practice and can vary in intensity and duration.

Common ways people observe upvas

• Duration: can be a few hours, half-day, full day, or several days. Some observe once a week or during special periods like Paryushan.
• Food limitation: many observe a lighter intake or skip cooked meals. Some eat only once a day (often after noon) or consume simple, non-root foods; strict forms may involve no food or water for part or all of the day.
• Allowed foods: often include fruits, dairy (in many lay practices), or specific allowed preparations, while avoiding grains, root vegetables, and sometimes even water depending on the vow.
• Conduct and mindset: during upvas, devotees commonly engage in heightened self-discipline, meditation, prayer, readings from Jain scriptures, and may perform pratikraman (repentence) and samayik (equanimity meditation).

Key differences you might hear

• Digambar vs. Shwetambar: there can be differences in the strictness of the vow, what is considered acceptable food, and whether water or certain foods are allowed during the fast. Local community customs and family tradition often dictate the exact observance.

Practical steps to begin 1) Decide the duration and level of observance (half-day, full day, or longer). 2) Set a clear intention and inform your family or the temple if you plan to fast in a community setting. 3) Prepare beforehand: adjust meals on the days leading up to the fast, choosing simple, Jain-friendly foods if you plan to eat. 4) On the day of upvas, begin with a short prayer or intention, perform a light Pratikraman if you follow that practice, and engage in calm, mindful activities (meditation, reading, or reflection). 5) Break the fast gently at the designated time with a simple, appropriate meal, avoiding overeating or heavy foods.

If you want, I can explain specific upvas rules for your Jain tradition (Digambar or Shwetambar) or point you to a JainKnowledge page that matches your question.