What can be the cause of persistent everyday flatulence (usually in the 2nd part of day) if there is zero abdominal pains and if the stool is perfect all the time? The only other minor symptom is slight bloating. I'm quite lean and muscular but from perfectionist point of view it looks as my stomach can be slightly enlarged in the evening.
Elimination of various food groups and supplements didn't really helped.
Yes, I do eat strict paleo with an exception of dairy. But yes, I tried eliminating it.
Nor digestive enzymes (which I BTW get a lot from my multivit - Animal Pak), neither pre/probiotics seem to influence the situation in any way.
This could be a symptom of low stomach acid. Take a couple HCl caps when you eat and see if it improves. Or you could take some apple cider vinegar with meals, as it stimulates stomach acid production. Typically those who are low in stomach acid will not be able to break down the color of beets and you can see it change the color of your urine (not your stool) to a pinkish hue.
What do you eat at lunch or for your mid-day meal? Too often I have reached for something quick and easy (e.g. canned salmon or tuna). I wouldn't say flatulence is a major issue, but bloating certainly is. When I have something I've prepared in advance, I don't have any issues. I suspect the substantial amount of salt in the pre-packaged items bloated me up.
Are you sneaking in any foods with sugar alcohols in them, especially ones that end in -ol (sorbitol, for example)? I started doing that, eating a couple sugar free popsicles after supper...I once timed a fart in the morning: 23 seconds! I was having shooting pains up into my shoulder from the gas build-up. Thought it was the fruit or veggies. Nope, it was the sugar alcohols.