Hi Cocosilk,
I still think that neither of the participants in that podcast were promoting Metformin for non-diabetics, they are both 'plugging' diet to control all metabolic syndrome disease. Ivor just happened to mention the newer research on Metformin in rodents - which may be invalidated. I actually like that he is open minded enough to consider all decent evidence, not just that for non-pharmaceutical solutions to Metabolic Diseases.
This guy in the lifespanbook thing is talking about disease prevention and so far as I'm aware, Metformin doesn't prevent any disease - if it did then surely it would be more popular than Statins!
But he doesn't even stop there, he then takes a wild speculation that age 'causes' Type 2 D , Dementia and other diseases. Which is just not true! Age means that patient has had longer to accumulated the bad stuff that causes the disease - otherwise everybody who dies of 'old age' would have T2D, Dementia, Cancer, CVD and other diseases for at least a few weeks before they die!
He then goes seriously off grid in suggesting that Metformin may lengthen life in an otherwise healthy individual - which is a huge leap from any actual evidence.