Do you think they were lying/cheating on the food they ate, as published in http://www.jbc.org/content/87/3/651.full.pdf ?
Do you discount the observation that "Inuit would often go 6 to 9 months a year eating nothing but meat and fish"?
Do you think the meat items mentioned in the JAMA are incomplete sources of nutrition?
Why "accidentally got required nutrition in ways similar to the Inuit"? After his many years of polar exploration and friendship with the Inuit, how can you dismiss that it was a learned practice?
Do you know of subsequent papers casting doubt on the results? Or replicating it, for that matter?
I found http://home.exetel.com.au/surreality/health/A%20Review%20of%... which says
> This level of protein intake may have been sustainable if hepatic enzymes were given time to upregulate (as there were several years between Stefansson living with the Inuit and the experiment at Bellevue Hospital and any previous upregulation of hepatic enzymes would have diminished), but the result for this limited study (where n = 1) indicates that the values shown in Table 1 are at least realistic, although we would speculate that individuals would tend to be at the lower end of the range for MRUS without a lead-in time for upregulating hepatic enzyme function.
which considers it feasible.
I'm aware that the article claims that these two went on an exclusive meat diet for a year. I'm saying that personally I don't believe the claim. Alternatively, that it's true but that they accidentally got required nutrition in ways similar to the Inuit.