Overall they're not courageous, obviously, but I mean relative to one another. Academics have some basic training in their field plus more specialized knowledge about their pet projects, but they don't seem to act on this knowledge very much -- perhaps because it's not very useful, so let's just stick with academics whose knowledge could be applied to real life.
Sometimes it's easy and painless to do so, like an engineering prof using a better type of building material rather than another for an addition to their house. But what about where it would cost them in reputation or social acceptance, which is what academics care most about (not money)?
For example, how many anthropologists or historians follow a low-carb diet? Other academics may not have a clue what happened to human health after we adopted an agricultural diet, but anthropologists do, and a fair amount of historians at least have the impression that it was for the worse. The most successful anthro / history book of the past several decades is Jared Diamond's Guns, Germs, and Steel, most of which chronicles how destructive agriculture was for human health. So even if this wasn't part of your specialty, you'd still recognize it as something that that Diamond guy talked about.
Conclusion for the real world: cut most carbs out. There can be no whining about taste, as how good something tastes is mostly due to fat, salt, and sugar. Most carb-eaters aren't eating cakes and ice cream all day, so they won't be missing much there. And they can eat all the fat and salt they want. Unadorned carbs taste like paper or grass -- nothing lost. The real reason they don't do so is that it'll make them stand out as a weirdo, even if they can explain why it's a healthier diet.
There is a mass suspicion about animal products in our culture today, so you can have a non-mainstream diet like vegans and not be considered weird (among academics anyway). But going the other way by relying more on animal products and eliminating grains -- now you are officially strange.
As far as I can tell, most anthropologists and historians don't apply this lesson at all in their real lives. Forget about those who say they don't care about their health (a lie almost always), and stick just with those who claim to want a healthy diet. Even they aren't majority low-carb.
Is there any group of grant-grubbers that does risk social disapproval to apply the wisdom or knowledge of their field to real life? Note the assumption -- that they possess such applicable wisdom to begin with. I'm not talking about an autistic economist who ruins his social life by contracting out the task of helping his friends to those who are specialists, which is more "rational" and "efficient." And, being less costly to the economist than doing them himself, are weaker signals of friendship, causing his friends to withdraw, so reducing his adaptedness to the highly social world we live in. This risk of social disapproval does not result from applying wisdom, as he has fundamentally misunderstood the purpose of helping out friends -- a big part of which is to give a costly (hence honest) signal of loyalty.
And I'm not talking about some sociologist who "just knows" that most of the differences in SAT scores are due to tutoring differences, and so spends a fortune for his kids to get top-rate tutors.
These people are fools whose decisions, if made commonly, would unravel humankind. I'm not ruling out anthropologists, economists, or sociologists -- but they surely wouldn't count based on the above examples. I know there are individual iconoclasts, but are there groups where most of them apply wisdom to real life despite the risk of broader disapproval?