As much as I think it's a great and comprehensive guide (the "science backed" link is the one I read most)... it should contain a warning because it suggests FODMAPS.
People like me with severe gut issues that are on the verge of colitis often have bad reactions to FODMAPS and 'fiber' which is usually full of FODMAPS. The word fiber is very poorly defined, as pointed out here: https://gut.bmj.com/content/gutjnl/48/5/587.full.pdf That article ends with some good advice about which fibers are more likely to be beneficial and shows that we are mostly guessing about the benefits of fiber just yet. The advice is given that way because it forces people to choose healthy foods, not because fiber has been proven to be the thing that helps.
High fiber = high pain for me. And crucifers + alliums = agonizing bloating and constipation (both together), for my gut. I probably need to work on my gut flora more before I can embrace this particular plan.