The potato consumption example is hardly a contradiction. It amounts to at most speculation by a Wikipedia author as to why the "glycemic effect" may be lower in South America, with no substantiation. Potatoes are bad for people, but in South America they are ok because they also eat fruit, beans, and vegetables? Most people don't eat only one food, so what is your point? Also, if I eat a candy bar, and then eat some fruit later, that does not lower the effect of the candy bar.
With regards to the American Diabetes Association reference by Dr. McDougall, one has to take into consideration when his article was written. Secondly, the reference you provided hardly shows much support for the glycemic index by the ADA, other than acknowledgement as a possible useful tool.
> The findings of a meta-analysis indicate that implementing a low-glycemic
> index diet lower A1C values by 0.43% when compared with a high-glycemic index diet.
0.43 PERCENT? Hardly a groundbreaking discovery.
> QUALIFYING STATEMENTS
> At this time, there is insufficient information to determine whether
> there is a relationship between glycemic index or glycemic load of diets
> and the development of diabetes. Prospective randomized trials will be
> necessary to confirm the relationship between the type of carbohydrate
> and the development of diabetes.
Harldy a strong endorsement.
> FINANCIAL DISCLOSURES/CONFLICTS OF INTEREST
> Janette C. Brand-Miller, PHD is on the board of directors of Glycemic Index Limited.
That report is not free of conflicts of interest.
Here is an article about the glycemic index currently at the ADA website.
> The Glycemic Index debate: Does the type of carbohydrate really matter?
> by Janine Freeman, RD, CDE
> As the low-carbohydrate-diet fad slowly loses steam, another may be moving in to take its place: the glycemic index fad.
...
> Some studies show small improvements in A1Cs among people who are attentive
> to the glycemic index. But reducing calories, weight loss, and basic
> carbohydrate counting have been shown to be more effective in improving
> A1Cs among people with type 2 diabetes than basing diet decisions on the GI.
> I don't suggest eliminating "high GI" foods in favor of "low GI" foods to
> gain better blood glucose levels for two reasons. First, there is not
> enough evidence yet to show that such an action actually will improve your
> blood glucose levels; and second, choosing foods based solely on GI will
> compromise healthy eating.
So it is evident that the ADA does not outright support and recommend the glycemic index.
Your final criticism is simply ridiculuous. Dr. McDougall writes of athletes and follows up with a recommendation for "anyone yearing to be strong and energetic". Hardly unrelated. I am speechless at your incredulity here. Secondly, he is not referring to old sports myths, such as carb loading, but replensihing glycogen reserves, which should be done after substantial activity, such as for one who is yearning to be "strong and energetic throughout the day."
Lastly, this has veered off topic - please provide a reference for your claim above that potatoes will "reduce your lifspan." I provided historical evidence of societies that lived on potatoes as a staple, with better health than the USA. You have done nothing other than nitpick and provide a Wikipedia URL that does not back up your claim, pretending that it contradicts an entire article by Dr. McDougall, without showing a single example.
Secondly, he is not referring to old sports myths, such as carb loading, but replensihing glycogen reserves, which should be done after substantial activity, such as for one who is yearning to be "strong and energetic throughout the day."
The feats of logic required to go from after substantial activity to such as for one who is yearning to be "strong and energetic throughout the day." are just too much for me to bear.
To get back on topic, just by citing the original article that this post is about, I can tell you that eating sweet potato instead of normal potatoes will extend your life, unless the change excludes some very important nutrients (unlikely).
With regards to the American Diabetes Association reference by Dr. McDougall, one has to take into consideration when his article was written. Secondly, the reference you provided hardly shows much support for the glycemic index by the ADA, other than acknowledgement as a possible useful tool.
> The findings of a meta-analysis indicate that implementing a low-glycemic
> index diet lower A1C values by 0.43% when compared with a high-glycemic index diet.
0.43 PERCENT? Hardly a groundbreaking discovery.
> QUALIFYING STATEMENTS
> At this time, there is insufficient information to determine whether
> there is a relationship between glycemic index or glycemic load of diets
> and the development of diabetes. Prospective randomized trials will be
> necessary to confirm the relationship between the type of carbohydrate
> and the development of diabetes.
Harldy a strong endorsement.
> FINANCIAL DISCLOSURES/CONFLICTS OF INTEREST
> Janette C. Brand-Miller, PHD is on the board of directors of Glycemic Index Limited.
That report is not free of conflicts of interest.
Here is an article about the glycemic index currently at the ADA website.
http://www.diabetes.org/glycemic-index.jsp
> The Glycemic Index debate: Does the type of carbohydrate really matter?
> by Janine Freeman, RD, CDE
> As the low-carbohydrate-diet fad slowly loses steam, another may be moving in to take its place: the glycemic index fad.
...
> Some studies show small improvements in A1Cs among people who are attentive
> to the glycemic index. But reducing calories, weight loss, and basic
> carbohydrate counting have been shown to be more effective in improving
> A1Cs among people with type 2 diabetes than basing diet decisions on the GI.
> I don't suggest eliminating "high GI" foods in favor of "low GI" foods to
> gain better blood glucose levels for two reasons. First, there is not
> enough evidence yet to show that such an action actually will improve your
> blood glucose levels; and second, choosing foods based solely on GI will
> compromise healthy eating.
So it is evident that the ADA does not outright support and recommend the glycemic index.
Your final criticism is simply ridiculuous. Dr. McDougall writes of athletes and follows up with a recommendation for "anyone yearing to be strong and energetic". Hardly unrelated. I am speechless at your incredulity here. Secondly, he is not referring to old sports myths, such as carb loading, but replensihing glycogen reserves, which should be done after substantial activity, such as for one who is yearning to be "strong and energetic throughout the day."
Lastly, this has veered off topic - please provide a reference for your claim above that potatoes will "reduce your lifspan." I provided historical evidence of societies that lived on potatoes as a staple, with better health than the USA. You have done nothing other than nitpick and provide a Wikipedia URL that does not back up your claim, pretending that it contradicts an entire article by Dr. McDougall, without showing a single example.