Short answer: Yes—traditionally Ekāsan (Ekasanu/Ekashana) is to be taken in one sitting and finished within one muhūrta (about 48 minutes) from the first morsel to the last.

Details:

• Reason: One-sitting, time‑bound eating reduces distraction, curbs indulgence, and minimizes himsā. Muhūrta (48 minutes) is the standard Jain unit used for many vows and practices.
• Sect notes:

- Shvetāmbara and Digambara both uphold “one meal, one sitting.” Many traditions advise completing it within one muhūrta. - Some follow a stricter discipline of finishing even faster (e.g., within half‑muhūrta), but one muhūrta is the common guideline.

• Practical points:

- Sit at one place, do not get up, and avoid taking anything again after you conclude. - Keep it in daylight and before sunset, as per your local maryādā. - If health requires, take guidance from your guru or local sangh.

Related:

• Ekāsanu/Biyāsanu (pachkhan and basics)
• “Why 48 minutes (muhūrta)?”
• Water rules around Ekāsan (timing with the meal)