What is the normal blood sugar level?

What is the normal blood sugar level?

Since I pay a lot of attention to my health
I have become interested in managing normal blood sugar levels.

However, I am not sure exactly what the normal blood sugar level is.
I am leaving this message to seek your help.

I found on the internet that the normal ranges for fasting blood sugar and post-meal blood sugar are different.

Fasting blood sugar is said to be between 70-99 mg/dL, and 2-hour post-meal blood sugar should be 140 mg/dL or less.
I'm not sure if this is correct.

Also, there is a possibility that normal blood sugar levels may vary depending on age.
There are also stories suggesting that it can vary depending on health status or lifestyle habits, so I was surprised?? lololㅌ

Is there anyone among you who is knowledgeable about blood sugar management?
What is the exact normal blood sugar level?
Someone who is well aware of effective ways to manage blood sugar levels.

Please let me know if there are any foods I should eat or avoid.

What lifestyle habits should be maintained to keep blood sugar within the normal range?
Please let me know if there are any foods or habits that are helpful.