Define on-topic and off-topic reasons in the help center

Question

One of the reasons on which many users are confused is on-topic and off-topic. If you once look at our meta home page, you will see that many questions are like Are questions about X on-topic here?

Are essential oil topic questions on-topic here?
Are recipes related questions on topic or should they be moved to cooking.stackexchange?
Are sorta-vegetarian diets on topic?
Is nutrition on-topic?

These are the questions I found and on the main site, we are seeing some questions. For example:

1. How to remove pesticides and harmful bacteria from fruits and vegetables?
2. Are mango seeds edible?
3. Is boiling orange or lemon peels and drinking it as a tea healthy?

From the above list,

• Question 1 is closed.
• Question 2 is closed but has a reopen vote.
• Question 3 is closed as off-topic.

To me question 2 and question 3 are off-topic. They fit in Health.SE. But one of our friends answered of the above questions and said this:

Being on topic somewhere else doesn't make them off-topic here.

To remove confusion about on-topic and off-topic, can we add the off-topic reasons in help center? Currently there is nothing defined as off-topic. Same applies for on-topic.

If we consider our personal opinions as on-topic and off-topic, it greatly affects the site quality. Adding these reasons would decrease duplicate questions and off-topic questions, and it would also reduce the number of disputed flags and burden on experienced users and moderators.

For example: The on-topic page of Hinduism.SE.

Keep your answers short and simple and add reasons why they are off-topic. Please one reason per answer.

Answer 1

I asked

Are questions asking for local or travel advice on-topic?

and it seems the answer is no.

But this should be interpreted sensitively I think: only close as off-topic if the answers are likely to be highly opinion based and go out of date quickly. A question with broader scope like "Vegetarian foods in Japanese culture" should be considered on-topic in my opinion, as answers are likely to help many people and remain useful over time

Answer 2

I've already asked about whether or not we should allow "Is X veg*n?" and the consensus is that these questions are off topic.

Should we allow questions on defining what is/isn't vegetarian?

I'd suggest a close reason along the lines of

Asking whether something is vegan/vegetarian is off topic as it's mostly down to personal opinion. They're broad lifestyles without anyone to lay out strict guidelines, so there wont be any definitive answers.