Talk:Glycemic index

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e·h·w·Stock post message.svg To-do:
  • The references at the bottom of the article need to be linked to relevant portions of the text, like the first one is.
  • The important information in the third paragraph - namely what is a high glycemic index, what causes it and why this may be a bad thing - needs to be presented sooner. The lay reader shouldn't have to wade through who invented it, technical definitions, undefined acronyms , and the number of people tested before getting the basic information he needs. Most readers don't want more than a basic understanding.
  • The illustration showing the effects of GI on the blood is incorrect. From reading it, it looks as if HI GI foods have a similar effect to low GI foods.
The illustration is correct. There is no difference in the glycemic response timing whatever the apparent GI is. This is what diabetics have to understand. Low GI food will give them an unwanted blood glucose spike just as high GI foods do. In other words, there is little for a diabetic to gain by using GI to choose their food. Ernie Lee BSc, Chemistry.
Chemistry degree or no, simple physiology of the disease and physics makes Ernie's comment wrong. The glucose content of an ingested food is directly proportional to how much glucose enters the bloodstream. Any given food's higher glucose content means more glucose gets into the bloodstream upon ingestion and a higher physiological response in the form of insulin production to be warranted. Anyone can see that that will cause a higher spike and a deeper crash. So, foods with a lower GI IE:Less glucose content do in fact equal a gain for not only diabetics but for anyone.
Glucose has one main difference from other sugars. It crosses membranes FAST, mainly to get into the bloodstream and immediately become energy in cells. It is the only type of sugar released into the bloodstream. All other sugars are converted into glucose before entering the blood.
Sucrose (cane sugar) is composed of 50% glucose and 50% fructose. High Fructose Corn Syrup (misnomer and oxymoron) is composed of 45% glucose and 55% fructose. High Fructose Corn Syrup is not Fructose at all. It is a new type of sugar very similar to cane sugar. The meaning of the word fructose is sugar from fruit. Corn is a genetically modified grain that looks like a fruit but its sugar does not match any other fruit sugar in that it contains glucose. Therefore, although it looks like a fruit it technically is not one. Real fructose contains only fructose which is the chemical opposite of glucose.

The graph[edit]

I don't understand the graph in this article. It appears to show two items with the same glycemic index, but served in different quantities. Maproom (talk) 12:38, 14 July 2009 (UTC)

I've deleted it. Maproom (talk) 16:23, 29 July 2009 (UTC)

Hi there,
It might be useful to have a graph of the change of blood sugar level for the reference food.
-- (talk) 15:57, 10 May 2011 (UTC)

The graph is not correct - blod glucose concentration can not be negative - the graph should be corrected or deleted — Preceding unsigned comment added by Olet (talkcontribs) 21:49, 2 January 2014 (UTC)

The graph is correct, but badly labeled.
The graph is really CHANGE in glucose after eating, and presumes that glucose was steady, without prior food or insulin action that had not yet run its course causing a drift (up or down) in glucose.
As such, the ordinate (Y axis) should be labeled "Change in Blood Glucose (mmol/L)".
The abscissa could be labeled more clearly as well: "Time (min)" or "Time after meal (min)". I don't know what "Tid" is supposed to mean.
Since the labels are part of the graphic, however, fixing the labels requires recreating the graphic, and it is already in Wikipedia Commons

DRLWorthington (talk) 02:26, 10 June 2014 (UTC)

Validity of the method... Repost....[edit]

-- (talk) 08:57, 19 January 2010 (UTC)

See more about it...

I consider this website is scientific based, as the statements require their backup/citation sources. As with the listed citations from Google scholar containing papers that the discussion section can not be missed, this site also has the article discussion sections for the writers to improve the quality of their writing. I just hope that wiki admin to be more polite and if they want to revert the writers edition, please provide the reasons-- (talk) 07:48, 20 January 2010 (UTC)


I saw an ad on TV for a weight loss program based on the Glycemic Index. If the GI can't be measured accurately, and if it has other problems (as stated in this article), then is this use in guiding a weight loss regimen scientifically valid? No matter what the answer, IMO it needs to be added to this article. David Spector (talk) 21:41, 16 April 2010 (UTC)

Re: Weight Control Section[edit]

In reference to: "In one study,[16] male rats were split into high- and low-GI groups over 18 weeks while mean body weight was maintained. Rats fed the high-GI diet were 71% fatter and had 8% less lean body mass than the low-GI group. Postmeal glycemia and insulin levels were significantly higher, and plasma triglycerides were threefold greater in the high-GI-fed rats. Furthermore, pancreatic islet cells suffered "severely disorganised architecture and extensive fibrosis." "

The category of 'Weight Control' uses this single study. It looks like a good study, but I think it is important to point out that the quote used is talking about the negative effects of high-GI upon the pancreatic islet cells, not the level of weight gained by the subjects. It is a great side discovery of this study. Further expansion of this would be very beneficial to give emphasis and differentiation to the separate points. — Preceding unsigned comment added by Scubanate3610 (talkcontribs) 23:58, 5 January 2011 (UTC)

Some further suggestions for "Criticisms" section[edit]

Could a further suggestion for the "Criticisms" section be that glycemic index of certain fruits may be how ripe they are? For example, pears have a high tendency to go from starch to sugar as they ripen; I always thought bananas were high in the glycemic index, but reliable sources have informed that this is only when they are ripe. I am not an expert on this, but any one who does have well-sourced information here could add it. ACEOREVIVED (talk) 15:46, 7 July 2011 (UTC)

Table of glycemic index[edit]

Hi, I've never edited or discussed any wikipedia articles before, but I was just reading about the glycemic index and noticed that the table lists "whole grains" as low GI and "whole wheat products" as medium GI. Wondering exactly what each of these were, I opened up link to both of them, only to find that they link to the same article (entitled Whole Grain, with a message saying it's been redirected from whole wheat if that was the link followed). This seems a little contradictory! — Preceding unsigned comment added by (talk) 08:56, 15 December 2011 (UTC)

The table is unreferenced and contradicts some of the articles linked at the bottom of the article. When I checked the GI of baked potatoes on one of the links it contradicted the article. The table definitely needs and update. Check out the table on this page: - wassname — Preceding unsigned comment added by (talk) 04:01, 27 January 2012 (UTC)

How can breakfast cereals have a Glycemic Index of 124 when the maximum is supposedly 100 for glucose? — Preceding unsigned comment added by (talk) 17:39, 12 May 2012 (UTC)

Need for reference to lucozade[edit]

Shouldn't this article refer to lucozade and dextrose sweets as things very in glycemic index ratings? They must be as they are used to treat hypoglycemia. ACEOREVIVED (talk) 23:20, 14 June 2012 (UTC)


"Glucose has a glycemic index of 100, by definition, and other foods have a lower glycemic index." this is false I think because there are foods with a glycemic index of 105 like dates this needs to be removed IMO Meteislam (talk) 14:19, 19 August 2012 (UTC)

Not sure where you're getting 105 for date GI, see this study ("The mean glycemic indexes of the dates were 35.5 for khalas, 49.7 for barhi and 30.5 for bo ma'an"), this study ("Mean glycemic indices ± SEM of the dates for the healthy individuals were 54.0 ± 6.1, 53.5 ± 8.6, 46.3 ± 7.1, 49.1 ± 3.6 and 55.1 ± 7.7 for Fara'd, Lulu, Bo ma'an, Dabbas and Khalas, respectively"), and Harvard health (Dates, dried: 42). Consistently nowhere near 105. HMman (talk) 13:34, 24 September 2012 (UTC).

Jenkens originally used a reference of white bread for calculating the glycemic index, making that 100, and carbs that contain more glucose, including glucose itself, have an index in excess of 100. Shifting the defining standard to glucose, making it 100, has the added benefit that 100 becomes the effective maximum, because there is nothing else, besides perhaps honey, that would raise blood glucose as high and for as long.

But the calculation of glycemic index depends on not just the absorption of glucose from the food at issue, but the disappearance of that glucose from the blood because of the insulin action generated by said food. This can vary from person to person, particularly for those with type 2 diabetes and its attendant insulin resistance. This article really should make clear that the experiment measuring the area under the curve of blood glucose after eating should only be done on normal subjects who do not have diabetes, not even pre-diabetes or abnormal fasting blood sugar. DRLWorthington (talk) 07:49, 10 June 2014 (UTC)

Dodgy table[edit]

So there is a table listing examples of 3 categories of food with low, medium and high GI, and "potato" appears in both the medium and high groups. Which ?Eregli bob (talk) 13:09, 24 September 2012 (UTC)

Table requires references and Accuracy section needs expanding and given greater prominence[edit]

I've added requests for references into the table especially for: the source of the GI ranges given; the source for the GI values of the examples given; and, as an example of the issues involved, for the "cranberry juice" entry. The article's section regarding Accuracy should be reflected in the article as a whole, and IMO it would be a benefit to the article if this section was given much greater prominence and expanded. Overall I think that the article is currently misleading to a "lay" reader as the variability between the values available for individual items is large while the GI range, both overall and within the bands, is relatively small. The potato entry noted by Eregli bob is another example of the fundamental problems with the utility of the GI LookingGlass (talk) 13:03, 23 November 2012 (UTC)

 As a stopgap measure I've moved the accuracy section to the top of the article so as 
 to balance the issues of variability better with the detailed internal logic of the 
 GI. The more I read the article though the more it seems to me that the detailed 
 calculations etc should come AFTER those sections that scope out the subject matter 
 and contextualise it, rather than before.
 LookingGlass (talk) 13:36, 23 November 2012 (UTC)

Does MGR discussion belong here uncritically?[edit]

"MGR" is introduced near the end of the article with no reference or adequate explanation. A little searching for "MGR" did not seem to show it as a well known index. It's explained on "The MGR Index Page", and appears be a "novel" measure. If I'm right, I don't think it should be given so much space on this Wikipedia page without any critical discussion. Mikeblyth (talk) 14:17, 2 November 2012 (UTC)


[10] Reference needs to be updated. I think it should be the following article but I'll let the original contributor insert it. — Preceding unsigned comment added by Jgchemie (talkcontribs) 23:58, 29 November 2013 (UTC)

Be bold! and fix it yourself if it needs fixing. —    Bill W.    (Talk)  (Contrib)  — 23:16, 2 January 2014 (UTC)

First paragraph revised, needs expert review[edit]

I corrected a number of writing problems in the first pararaph; now it needs checking by a subject matter expert. Here are some of the problems I corrected:

  • It's usually better to define the topic first and then describe it.
  • It was unclear why the GI "attempts" to measure the variation. Wrong verb I think.
  • The GI does not measure the variation. Again wrong verb; the measurement was done in a lab.
  • GI does not express a variation (A-B), it is more of a ratio (A/B) with respect to glucose.

The part about carbohydrates needs to be checked by a subject matter expert. The following questions are still unclear: 1) Does only the carbohydrate component of a food cause a rise in blood sugar level? 2) What does it mean that the GI only takes into account the carbohydrate contained in the food. When the GIs were determined in a lab, how was this be done and how were the effect of fats etc. accounted for and/or removed from the results?

Hopefully an expert can clear up this confusion. 3dimen (talk) 01:18, 9 August 2014 (UTC)

External links modified[edit]

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Recent changes[edit]

I am in the process of making a substantial number of changes to the article. I would be grateful if someone who understands the subject can review them. Rjm at sleepers (talk) 10:43, 4 January 2017 (UTC)

@Rjm at sleepers: the article certainly needs a major review; it's grown very "bittily" and doesn't read as a coherent whole. It's also important to source carefully some of the statements. GI values for foods, for example, can vary greatly in different studies. As an example, go here and put in "sweet potato". GI values vary from 44 to 94, depending on the study and the cooking method employed. The average comes out around 60, which justifies the usual description of sweet potatoes as "medium GI", but it is only an average. Peter coxhead (talk) 11:26, 4 February 2017 (UTC)

Watermelon and fructose[edit]

This article has a sentence that begins by referring to watermelons, and then has a sentence that tells us that fructose has a low glycemic index. Watermelon and fructose are in different categories - watermelon is a fruit, fructose is a sugar that is common in fruit. This article would be better if it had a sentence that began by talking about glucose, then a sentence talking about fructose. I suggest this article is amended so that it has an article on glucose, pointing out that glucose is high on the glycemic index, and then a sentence on fructose, telling us that, compared with glucose, fructose is not all that high on the glycemic index. Vorbee (talk) 16:46, 22 October 2017 (UTC)