Hello Welcome to HCM. Thanks for posting your query. And it's superb that you have given all the details required.
With young guys, 5mm calculus in
kidney there's nothing to worry. This is point number 1.
So,do not worry. I've seen huge calculus than this.
Does this cause severe pain?
If occasional tolerable pain then neglect it.
Drink lots of water, around 4 to 5 liters a day.
And if it's troubling you with pain then take tablet
ultracet for time being.
There is absolutely no indication for surgery or any intervention for 5mm stone.
But having said that, do keep a track on that stone. Sometimes it may pass off by its own.
Or else, it may grow large. Then probably you'll need something called
ESWL.
So as of now do not worry. Be calm and do as I advised.
And coming to the second query, diet. There are so many papers published regarding this but there's no standard protocol .
Avoid
1. Junk food.
2. High intake of salt
3. Cut down on meat..
Hope this helps, and you can contact me anytime regarding this..