Friday, 28 December 2012

Plant Positive Strikes Back: Nutrition Past and Future

Plant Positive has released a brilliant new series on YouTube titled 'Nutrition Past and Future', featuring 44 videos that address the misleading claims of Paleo, Primal and Low-Carb diet advocates including Gary Taubes, Robert Lustig, Loren Cordain, Mark Sisson, Robb Wolf, Andreas Eenfeldt, Anthony Colpo, and members of the Weston A. Price Foundation among others. This new series expand on Plant Positive's two previous video series, 'The Primitive Nutrition Series Playlist' and 'The Primitive Response Playlist'.

The Journalist Gary Taubes

Taubes gained prominence as an advocate of the low-carb diet following the publication of his article "What If It's All Been a Big Fat Lie?" in the New York Times in 2002. A follow-up article expressed the concerns of scholars that Taubes interviewed who complained that Taubes misinterpreted their statements and ignored much of the research that they presented, including research linking red meat with colorectal cancer. It was already clear from this point that Taubes was a snake oil salesperson and Plant Positive makes this fact even clearer in Nutrition Past and Future which in particular addresses Taubes's book Good Calories, Bad Calories

The Journalist Gary Taubes 1: Controlling History

Ancel Keys and John Yudkin

In Nutrition Past and Future, Plant Positive addresses the controversy over the classical research produced by Ancel Keys and John Yudkin. The first video below addressed Keys classical paper from 1953, Atherosclerosis: A problem in newer public health regarding the cross-sectional study of dietary fat intake and coronary heart disease mortality in six countries, not to be confused with the Seven Countries Study which was a longitudinal prospective cohort study published a number of years later. Plant Positive explains Keys views on nutrition and the literature at the time of this publication, as well as the plausible reasons as to why Keys selected the six specific countries to be included in the analysis. As Plant Positive explains, Keys omitted countries from the analysis that experienced major population shifts and changes to diet caused by the war, as well as those countries with very small populations. Keys also addressed this issue in a later in response to the international comparisons carried out by Hilleboe who included countries that had experienced these significant populations shifts and changes to diet.1

Plant Positive also pointed out that Keys limited the analysis only to countries that used reliable death records which classified deaths closely to that of international standards, and that Keys clearly asserted that:2
So far it has been possible to get fully comparable dietary and vital statistics data from 6 countries
Another point that the cholesterol skeptics ignore is that even when all the other countries were considered, intake saturated fat was still a strong predictor of coronary heart disease mortality [reviewed previously]. Even Hilleboe admitted this in 1957:1
Human diets with unrestricted fats, especially some of the saturated fatty acids, appear to be associated with coronary atherosclerosis, particularly in adult males
Keys however criticized Hilleboe's claim that this association ‘is not a causal relationship’ as Hilleboe provided scant evidence to refute the possibility of a causal relationship.1

The Journalist Gary Taubes 3: Ancel Keys Was Very Bad 1

The Journalist Gary Taubes 4: Ancel Keys Was Very Bad 2

As can be concluded from Plant Positive’s videos, it is ignorant to suggest that Ancel Keys cherry-picked these six countries without giving the reason for the selection criteria. In Denise Minger’s post regarding Ancel Keys 1953 paper where she attempted to plagiarize Plant Positive’s work, like Yerushalmy and Hilleboe, Minger ignorantly claimed that ‘Keys cherry-picked six countries and never told us why.’ It is clear that Minger has either simply not read or is ignorant of the data presented in the Keys paper that she criticized, yet still claimed that she ‘did a deeper analysis of the 1950s data than Keys himself probably did.3 This is the same level of ignorance that Minger applied to her criticisms of the China Study [reviewed previously].

Plant Positive also provided an informative review of the controversy over John Yudkin's claims about sugar intake and the risk of  coronary heart disease.

The Journalist Gary Taubes 5: John Yudkin Was Very Good

In a later review, Keys again addressed Yudkin’s claims regarding sugar intake and coronary heart disease in international comparisons:4
In regard to international comparisons, there are countries with a high per capita consumption of sugar and of saturated fats; those countries tend to have high CHD death rates. And there are countries with low per capita sugar and saturated fat intakes; these have low CHD rates. When all these countries are put together, statistical calculation naturally shows CHD mortality is correlated with both sugar and fat intake. However, partial correlation analysis shows that when sugar is held constant, CHD is highly correlated with per capita saturated fats in the diet but when fat is constant there is no significant correlation between sugar in the diet and the CHD incidence rate. It should be noted, too, that Yudkin carefully avoids mentioning the fact that 2 countries with the highest per capita sugar consumption, Cuba and Venezuela, suffer low CHD mortality; it is notable that the dietary intake of estimated fats is low in both Cuba and Venezuela. 
Another flaw in Yudkin’s hypothesis about sugar and coronary heart disease that Plant Positive addressed was the contradictory evidence from animal experiments of atherosclerosis. When diets rich in dietary cholesterol and saturated fat, such as egg yolks are used to induce atherosclerosis in non-human primates, the atherosclerosis process has actually been reversed when these atherogenic components are replaced with chow very rich in sugar.5 6 This does not suggest that sugar should be considered a heart healthy food, but does emphasize the fact that sugar alone cannot induce atherosclerosis in the absence of dietary cholesterol and elevated blood cholesterol, and therefore cannot not explain the coronary heart disease epidemic.

Primitive Populations Revisisted

In Nutrition Past and Future, Plant Positive reviewed a number of high quality studies that strongly contradict the claims of low-carb advocates such as Taubes. These studies include the observations from the China Study and numerous earlier observations in China that are in general agreement with Dr. Colin Campbell's findings. For example, the observations that the nomadic Sinkiang in northern China who consumed diets rich in organic grass-fed animal foods experienced a 7 fold greater incidence of coronary artery disease than the Chinese living in Zhoushan Archipelago who consumed a diet much richer in plant based foods. These findings resemble even earlier observations from the 1920's of the nomadic plainsmen in Dzungaria in northwest China and across the border in Kyrgyzstan who consumed enormous amounts of organic grass-fed animal foods and experienced severe vascular disease at young ages [reviewed previously].

The Journalist Gary Taubes 15: Pesky Facts

In Nutrition Past and Future, Plant Positive provides an very informative analysis of the blood cholesterol in hunter-gatherer populations and the factors, such as parasites which are responsible for the observed low blood cholesterol in many of these populations. As Plant Positive addressed, George Mann contributed unnecessarily to the cholesterol confusion. Nevertheless, Mann has provided an excellent critique of a poor quality autopsy study authored by Biss et al. that cholesterol skeptics frequently cite to claim the traditional Masai did not develop atherosclerosis. Mann stated:7
Biss et al. have published their findings with 10 autopsies of "Masai" done at the Narok District Hospital in Kenya. They described "a paucity of atherosclerosis" with only "occasional fatty streaks and fibrous plaques" in subjects presumed to be Masai. The authors did not give details of selection of the subjects, a description of the causes of death, the methods of evaluation or even the ages. They measured the thickness of the coronary arteries with a caliper and found that "the Masais' coronary arteries had much thinner walls than those of whites in the U.S., matched for age and sex." Those measurements were not shown nor was the comparison population further described.
It is interesting that the cholesterol skeptics hail George Mann’s work as good science, but ignore this criticism about one of their frequently cited studies. Mann's critique suggests that the autopsies described in Biss et al. may not have even been carried out on Masai and that the authors did not even provide the information required to make an informed conclusion about the degree of atherosclerosis in this very small sample of people presumed to be Masai.

Ancestral Cholesterol 1

Ancestral Cholesterol 2

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