I bowed out of the doping conversation a couple hundred posts ago, but apropos of the magic legs ketone drink, in an article yesterday Froome was quoted as saying "All of it is absolute rubbish. From what I understand the team nutritionist looked at ketones but said he didn’t think it would be something for endurance cycling. It is not something that interests us."
The article is
here. On the off chance that you don't have an online subscription to the Times of London, Betsy Andreu has quoted the article on her FB page.