Following on I find this discussion on Effect of diets and T2DM where they varied the different parameters in a non meat diet plan and found
"the relationship of the various diet components among two groups of women, including fat, fiber plus sucrose, and the risk of T2DM. After adjustment, no associations were found between intakes of fat, sucrose, carbohydrate or fiber and risk of diabetes in both groups"
I find this conclusion worrying but there is no reference to a study that I can follow to see what their test methodology was. The duration of the monitoring is not stated, so was it a couple of weeks or 10 years on the altered diet? How are they estimating the risk. I wonder. But it forms the cornerstone of Barnards claims.
Edit: Here it is.
https://www.ncbi.nlm.nih.gov/pubmed/1315120
From Harvard and authored by Walter Willett and appears to be the Harvard Nurses study, which is still ongoing.
Apparently it uses BMI as the measure of risk of being T2D. OooooPsie
Moving on but with the same section of the original starting point, I find the following study referenced
https://www.ncbi.nlm.nih.gov/pubmed/1951264/
This study is being used to prove that an LCHF diet causes T2DM, and in fact seems to demonstrate that there is a linear relationship between fat intake (in increments of 40 g/day) and the worsening of a GTT test,
The study starts off by declaring that
none of the participants at baseline had a diagnosis of T2DM, but later on the test method compares those with T2DM against those with Glucose intolerance. and demonstrates that as the diabetes blood sugars rise, then increasing fat seems to increase the depth of T2DM. It is not at all clear from the summary what is actually going on in their testing, or what it is they are actually monitoring, or how they are controlling other dietary influences. One weakness is that the test uses the previous 24 hours diet as the registered baseline for each class, and the criterea are not described.
The study itself is a John Hopkins Uni report, and is hiding behind a paywall. I wonder why? Most other reports get put into Pubmed or similar public archive, but to stay behind a paywall implies that this is privately funded by persons unknown who wish to protect their interests.
There is something about this study that I am uneasy about. Something about it is fishy but I cannot see what. It is nothing to do with vegetarian diet as far as I can see, but clearly disses LCHF.
OK found something. The original San Luis trial was study to determine the prevalence of diabetes T2DM between Hispanics and NonHispanic Whites. The inital screening describes the GTT testing etc to identify diabetics in the group for further research, and they then moved onto the study, which is actually published in Pubmed and NCB! for free access.
So someone either hacked or gained access to that initial screening data and attempted to extract different info from it, which is why I had so many questions - those questions were not asked in the original trial.
Edit there was a pukka report that answers some of the queries,
https://www.andeal.org/worksheet.cfm?worksheet_id=250576
OK so the whole thing is estimated and modelled from the baseline data and the 20 people that went on to develop T2DM after 2 years. So it assumes that they kept to the same diet in that period? Very very weak methadology. There is no apparent measurement of carbohydrate intake at baseline, or the follow up so it is not viable to assume those parmeters would also remain constant.
No way is this a valid study.