In Jainism, a weekly practice where you restrict certain foods is generally called a “vrat” (vow). Depending on how you do it, it may have different specific names:

1. Upvās (उपवास)

- Many people keep weekly upvās on a fixed day (e.g., every Friday). - Some take no food (only boiled water in daytime), some take very limited food.

1. Ekasana / Biyasan (एकोशन / बियासन)

- Ekasana – eating only once in the day, in one sitting. - Biyasan – eating twice in the day, in two sittings. - Often used as a weekly or festival vow.

1. Ayambil (आयम्बिल)

- One very simple, tasteless meal (no oil/ghee, milk products, sugar, many spices, etc.). - Some people take Ayambil every week on a fixed day as a special vrat.

1. Partial tyāg (त्याग) – giving up only certain items

- For example: - “Ras-tyāg” – leaving tasty items like sweets, fried food. - “Farasan-tyāg” – leaving fried snacks. - This can also be done weekly as a small vrat.

So, in simple words:

• The general name is: weekly vrat / upvās.
• The specific type depends on what you actually do: Upvās, Ekasana, Biyasan, Ayambil, or some tyāg.

You can read more about different types of Jain fasts here

And about Ayambil specifically here