Here's an example that's unrelated to diet or climate science--two of my hobby-horses.
Does psychiatry, especially in its reliance on mood-altering medications, do more good than harm? What is the evidence? Robert Whitaker has written a book exploring this question in some detail. Of course he acknowledges that some patients are helped by drugs, and would be unlikely to get the same kind or degree of help in any other way. But what about large groups of patients, prescribed drugs over a long period of time? What are the results in comparison to no drugs are far fewer drugs?
Here Whitaker tells the story of how his book was taken apart in a review by a psychiatrist--who is obviously trying to defend the status quo, regardless of the science.