Short answer: No. During Paryushan, eating food kept overnight (leftover/basi) is avoided.

Why:

• Ahimsa: Overnight food develops many minute life-forms; eating it increases himsa.
• Sanyam: Paryushan is for heightened purity and restraint, so only fresh food and fresh boiled water are taken.

How to observe properly

• Prepare fresh food each day and eat before sunset.
• Use only same‑day boiled water; discard after sunset and boil fresh next day.
• Many also limit to simple meals (e.g., ekasana/ayambil) and avoid greens or certain vegetables as per their family/tradition.

Sect notes

• Shwetambar: Basi-tyag (giving up stale food) for all 8 days is standard; only same‑day boiled water in daylight.
• Digambar (Das‑Lakshan): Stale food is also forbidden; many keep ekasana/ayambil or fasts with strict daylight rules for food and water.

Compassionate exception

• If someone is ill or medically required to eat, Jain conduct allows necessary intake as “medicine.” Keep intention pure, minimize harm, and do alochana/pratikraman afterward.

So, during Paryushan, do not eat leftovers the next day; take only fresh, same‑day food and water before sunset.