It’s not necessarily that fallacy. I just don’t nutrition science is a great place to appeal to authority. I see it as similar to arguing for the status quo when the church held that the earth was flat. What we are doing is not working, and we should at least consider listening to dissenting voices.

It might turn out that they’re arguing the earth is round, or maybe they’re arguing that the earth is a doughnut shape. The validity of what anyone says has to stand on its own merit. But shutting it down because someone is “a joke” (amongst a science that is largely, itself, a joke), is not conducive toward improving our understanding.