This was tweeted by Jason Fung
http://www.bmj.com/content/351/bmj.h4023/rapid-responses
Can not see the whole of the piece but the obvious thing is that he was cured …
But more interesting read the comments and remeber the source of this is the BMJ - this comments will be from well informed people.
I think it is vital when top line journals are posting this there are far more important than some of the ‘studies’ out there that simply do causation and not how !
Yes. While I’m finding that in the science community “anecdotal evidence” is sometimes deemed as untrustworthy, there is absolute authority in people’s personal victories. Especially when the science backs it all up. 
examples are greta and proven it works, I may be wrong but have I missed the examples of where Keto made a T2 or other people even sicker ?