"Very" vs. "Really"
Sometimes I am confused about using "Very" or "Really".
Are they mostly used in the same context? If not, how to distinguish the difference?

I remember one time a British friend asked me: How is the meal?
I answered: It's VERY delicious. Then he corrected me: the better way to say it would be: It's REALLY delicious.

So my question is are there any rules to follow?

Thanks in advance.Thanks Tess W for providing the link with a clear explanation of the use of "Very" vs. "Really".
I paste the information below for those who may have the same question as me.

Source from: https://grammarstammer.weebly.com/words-to-the-wise/really-vs-very

Really and Very are words that add emphasis and intensity to what is being said.
They are not differentiated as being formal vs. conversational. In fact, if I were to judge, they are both informal and would rarely be used in a technical/scientific paper. For example, you could write, "The car is really small" and "The car is very small". Both sentences mean the same thing - there is no nuance in meaning. But why not enrich your vocabulary by using words like "extremely" or "incredibly".

Let's get down to business.

REALLY: An adverb, which means that it's used to describe adjectives, verbs, or other adverbs.

VERY: An adverb, but with one hitch - it cannot modify verbs.
Example:
I really like it. (correct)
I very like it. (wrong)

But then it gets extra complicated because Very can modify the appearance of verbs in the past participle form, but only because these have been established as adjectives.
Example:
I'm a very driven person.
Explanation:
Driven, although the past participle of Drive, is actually supporting the adjective role in this sentence, describing the kind of person I am.

Really and Very can be interchangeable when they both modify an adjective.
Example:
She is a really interesting girl.
She is a very interesting girl.

However, there are times when they cannot be replaced by the other. Like I said before, Very cannot modify verbs.
Example:
I really think she is an interesting girl. (correct)
I very think she is an interesting girl. (wrong)

One more difference:
Really can also be used as an interjection - to show surprise or exasperation.
Example:
Me: I saw the band Twisted Sister last month.
You: Wow, really?

Question

"Very" vs. "Really"
Sometimes I am confused about using  "Very" or "Really". 
Are they mostly used in the same context? If not, how to distinguish the difference?

I remember one time a British friend asked me: How is the meal?
I answered: It's VERY delicious. Then he corrected me: the better way to say it would be: It's REALLY delicious.

So my question is are there any rules to follow?

Thanks in advance.Thanks Tess W for providing the link with a clear explanation of the use of "Very" vs. "Really". 
I paste the information below for those who may have the same question as me.

Source from: https://grammarstammer.weebly.com/words-to-the-wise/really-vs-very

Really and Very are words that add emphasis and intensity to what is being said.
They are not differentiated as being formal vs. conversational. In fact, if I were to judge, they are both informal and would rarely be used in a technical/scientific paper. For example, you could write, "The car is really small" and "The car is very small". Both sentences mean the same thing - there is no nuance in meaning. But why not enrich your vocabulary by using words like "extremely" or "incredibly".

Let's get down to business.

REALLY: An adverb, which means that it's used to describe adjectives, verbs, or other adverbs.

VERY: An adverb, but with one hitch - it cannot modify verbs.
Example: 
I really like it. (correct)
I very like it. (wrong)

But then it gets extra complicated because Very can modify the appearance of verbs in the past participle form, but only because these have been established as adjectives.
Example:
I'm a very driven person. 
Explanation:
Driven, although the past participle of Drive, is actually supporting the adjective role in this sentence, describing the kind of person I am.

Really and Very can be interchangeable when they both modify an adjective.
Example:
She is a really interesting girl.
She is a very interesting girl.

However, there are times when they cannot be replaced by the other. Like I said before, Very cannot modify verbs.
Example:
I really think she is an interesting girl. (correct)
I very think she is an interesting girl. (wrong)

One more difference:
Really can also be used as an interjection - to show surprise or exasperation.
Example:
Me: I saw the band Twisted Sister last month.
You: Wow, really?

Answer

Ya Wen,
There are some similarities and differences. Both are adverbs that intensify the intensity of gradable adjectives.

Imagine two extremes of a temperature scale. At 100 degree Celsius, pure water boils. At 0 degree Celsius, it freezes. "Boiling" and "freezing" are participial adjectives that are ungradable because they are two extremes on a scale. The water is either "boiling" or "not boiling; it cannot be "slightly boiling". "Hot, on the other hand, is a gradable adjective. You can use some adverbs of degree such as "quite", "very" or "really" to modify the "hotness" of something, just as you would adjust the temperature of an oven with your thermostat.

A: The water is very hot. 
B: The water is really hot. 
Here is one difference: In A, the water is hot enough to scald you badly. In B, you are telling someone truthfully or factually that the water is hot. We use "really" to emphasise on the truth or reality, and to convince someone of what we are saying.

D: He really kicked me!
E: He very kicked me!
E is wrong as "very" does not modify another verb (i.e. kicked). "Really," on the other hand, does.

F: I like it very much.
G: I like it really much. 
We do not use "really" to modify certain adverbs such as "much".

Here you go: similarities, differences and rules.

Answer

I think we have a difference of opinion on usage between the USA and the UK here :) I'm from England, and "very delicious" sounds odd to me. Garry (above) is from the USA, and says it's fine; it's just one of those things! I think your friend was a little harsh to correct you, though. Here's a link you may find useful

https://grammarstammer.weebly.com/words-to-the-wise/really-vs-very

Answer

So far, you haven't really had a full or satisfactory answer. 
I can explain exactly why your friend corrected you.

If you comment on this answer, I'll give you a grammatical explanation of your mistake.

Answer

Your friend in this instance was over correcting you, I think what he wanted to point out is, that in informal daily speech, Brits sometimes say "really" to mean exactly the same as "very".

We also say "so" to mean exactly the same as"very" and "really" 
we often use "so" when talking about a person personality "you are so annoying" is same as "you are very annoying" or "really annoying".

Answer

Really and Very are simillar in that they are both adverbs. They modify or qualify adjectives and verbs. They differ because really can be used as an interjection and very can be used as an adjective.

Example:

Very: That is the very item I want to buy.

Really: (person 1) I am coming to visit you in July. 
             (person 2) Really?!

I hope this helps:)