Can't speak for climate and health science, every time I bring up this topic, it shows they are really different from my own experience.

By the way, are there still many experts who are anti-fat and pro-carb? In my experience, talking with my sister who graduated as a mainstream doctor, it doesn't seem this is the main narrative anymore. It seems to be mostly focused on low sugar. Sugar and processed food are the root of most evil in current-day cuisine. And that's agreed upon by the mainstream. Fat is not the big evil anymore; that was the case during my parents' generation when I was growing up.

As for (red) meat, the mainstream is trying not to push it too much as it is likely not sustainable if everyone lives on beef alone. It is a very resource-intensive type of cattle (this is true, regardless of whether you believe in climate change). But from a health perspective, people who understand "a percentage on a percentage" realize that the supposed increase in cancers, etc, is negligible in the big picture and understand the benefits of eating something that is by definition full of nutrients.

This is based on my experience in Korea and Europe. I can't speak for the prevailing narrative in the US.