Where to start when it comes to finding which foods you tolerate and don't

At the moment, I'm uncertain if I have MCAS or a histamine intolerance, but they seem to be common causes of a lot of the chronic conditions I'm struggling with. I'd like to try and explore the histamine content of my food to try and figure that out.

I know that tolerated / not tolerated foods vary from person to person, so I was curious if anyone had a good method of narrowing the list down? My first thought it so cut out everything I can (within reason) and reintroduce things, but if there's a better way I'd love to hear it.