> maintaining a healthy weight have long been the most important factors in cancer prevention. I don't think that's controversial

You'd be surprised. There are unfortunately many people who will aggressively attack anyone suggesting diet, exercise or weight management in any way to address obesity-related diseases. In their worldview, people have no agency to change their eating habits, and advising patients to do so is unhelpful, they exclusively want drugs, surgery or other accommodations to address issues.