The theory they were proving out was that the fat built up in the pancreas was tricking their body into seeing the wrong amounts of insulin.
[ edit ] Adding link for Dr. Fung's research [1] as mentioned in a reply by SteveCoast
Fung has lots of articles on Medium and /r/fasting is a great resource. Fung and also Taubes books are great and point out he maddening simplicity, that diabetes is high insulin is high sugar intake and that we treat it with... higher insulin. It's insanity, and because we can't see the wood for the trees we have smart people go study things like how much titanium you have in your body rather than solving the actual problem of carb intake.
Why can't we have both? We have a lot of smart people and the more ideas we have go through the scientific process of becoming a recognized treatment, the better. It doesn't take an army of smart people to create solutions, just a few. It's drive and motivation to solve problems that's in limited supply.
if we can reduce type 2 diabetes without reducing carb intake, that's a win.
What is great about problems during fasting though, generally speaking, to solve them is as easy as breaking the fast.
There are fasting clinics where doctors monitor the urine output from patients to determine if their body is expelling too many toxins at one time, and help control the fast.