Nutritional science is a great example of this. There are “thought leaders” spearheading different nutritional belief systems (ideologies?) that completely disagree with each other and <i>all</i> back up their claims with what seems to be recognised well-done science. And they <i>all</i> have a long list of real world success cases showing that what they are promoting works for <i>some</i> people. I have moved from one extreme to another, from vegan to keto, finally realising that there is no one-size-fits-all solution for everybody. You have to try different things (vegan/keto/…) and get the medical/blood tests done to see if it works for you. If your health improves doing X then you are moving in the right direction.