Gary Taubes and Peter Attia where championing Ketogenic diets at a time when people where violently opposed to it. In fact, they are a big reason why my doctor now tells everyone working with weight loss to start there. There have been reports for years on /r/keto and other places of people "accidentally" forcing diabetes into remission. So none of this is surprising. Yes, there is a lot of marketing here, but Taubes and Attia have earned the right to try and change people's minds about things.