Talk:Glycemic index
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[edit] Contradictory Unclear Statements
"Unrefined breads with higher amounts of fibre generally have a lower GI value than white breads, but, while adding butter or oil will lower the GI of bread, the GI ranking does not change. That is, with or without additions, there is still a higher blood glucose curve after white bread than after a low GI bread such as pumpernickel."
Does anyone understand what bread GI or GI ranking is (with or without butter) at any point in time after reading this?Ace Frahm 08:47, 26 February 2007 (UTC)
- It says, basically, more fiber lowers GI; buttered bread has lower GI; Low GI bread always has a lower GI than high GI bread regardless of added butter. —The preceding unsigned comment was added by 66.153.117.118 (talk) 21:56, 4 April 2007 (UTC).
[edit] Inherent Dangers
This page is especially for common folks, yet chocolate is listed. This could lead to the naive assumption that any refined chocolate product (which usually contains massive amounts of processed sugars) are okay to eat. This should be clarified. Go ahead and lemme know what you think about this.193.170.48.34 16:17, 7 June 2006 (UTC)
To say these are "inherent dangers" is nonsense. The use of the glycemic index or any other dietary lifestyle requires some common sense. The GI is simply a tool that covers one aspect of eating - mainly choosing "smart" carbohydrates. Of course a person's diet should not be high in chocolate or potato chips or lard - that's a no-brainer. Just because they are low GI doesn't make them a healthy food choice.
[edit] Definitions
Okay ... but what is the Glycemic Index ? Where do these numbers come from? Are they arbitrarily assigned or do they represent the end product of some calculation? I think an encyclopedia entry would have to relate this! Zuytdorp Survivor 22:47, 8 Feb 2004 (UTC)
- I believe they're measured by having a group of people eat 100 grams of <carbohydrate>, then taking blood samples every few minutes to measure the blood sugar level. The index value is either the height or the time of the average peak relative to glucose. -- wwoods 08:32, 18 Mar 2004 (UTC)
wwoods is on the right track. I'm not sure about the "every few minutes". I have read that the index value is based on the area under the graph, but that doesn't quite square in my mind with the information that the index is supposed to provide, so I want to research this more before (if nobody else does it sooner) editing the page with the info rightly requested by Zuytdorp Survivor.
Right now I'm doing a major edit, which includes some deletions, so I want to explain the main features. For context, I've just been diagnosed with diabetes and so I'm doing a lot of research to understand GI and other issues so that I can repair what is repairable and learn to manage and live with what is not.
Key changes:
Deleted erroneous information about sugars and starches/complex carbohydrates. Dietary advice used to favour complex carbohydrates over sugars because the notion made sense that the body takes longer to process complex carbohydrates than sugars. After all, the processing involves breaking them down into sugars. However, research proved conclusively that the notion was incorrect. The starch in many foods is converted to blood glucose faster than table sugar! These findings were what prompted the development of the GI as an indicator of carbohydrate quality.
Deleted the examples of GI values - too few to be useful. I'll be working on something useful.
Deleted the links. One was less informative than any of the many pages I've found in my research. The other, with a GI list, was (like nearly all the GI lists I've found) an ad for a book. There are a great many such lists on the web, and I can't see grounds for selecting a particular one to promote. Moreover, short GI lists, designed to be of practical help to individuals, are culturally restrictive. They list foods thought to be most likely to be used by their target audience.
I question the practice of linking to pages that provide info that should be in Wikipedia, but maybe it's valid as a stopgap, an aid to readers while content is in preparation. So I've linked to what I understand to be the most comprehensive and authoritative list of GI values, in three ways. One is a searchable database, presumably up to date. Then there's the research group's data published in the American Journal of Clinical Nutrition in 2002. Finally, there's a simplified version of that list published by Rick Mendosa.
My intention is to try to condense the information from these sources into a list that is still comprehensive and culturally unbiased, but of practical use to individuals who want to control their carbohydrate diet. --Richard Jones 11:37, 20 Mar 2004 (UTC)
I think the last paragraph is wrong. GI is the measurement of how the blood sugars raise: foods with fat do lower the rate of which they raise. So how is it a 'false' rating? Fineform, if that was the source at which you got the information, was trying to say that foods aren't healthy just because of a low GI; not that they don't have a false GI. That, in any cae, is biased in favor of a low fat diet. Juan Ponderas
The comment suggesting that a short fall of the GI is that it only measures glucose should be removed. While this is true that it measures only glucose, it is not a shortfall as it is *glucose* we are concerned about and high glucose levels (spikes) which have been implicated in disease aetiology. It actually does measure the glycemic response from fructose (after conversion to glucose) as low GI and is therfore extremely valid. This explains why honey has a low GI and table sugar a moderate one. The glycemic response correlates very strongly with insulin response. The statement written in the article is incorrect. I will add to this article soon hopefully when I have more time.--sd 03:58, 2 Feb 2005 (UTC)
Just wrote a major revision and tightened it up in many places. I have a good image to load but need to get clearance from the University of Sydney first.
[edit] Booze
The sentence "Alcoholic beverages are also low GI" seems like, at the very best, a gross oversimplification. Beer contains maltodextrin, which has a relatively high GI, right? Let's at least use a qualifying word like 'some,' or get specific and talk about red wine, which as a lower GI than beer.
Beer contains, on average, 10 g of carbohydrate per serve. The amount is negligible for raising blood glucose levels when drunk at a reasonable rate. If, on the other hand, someone were to drink 6 beers in an hour than it may become significant. It is therefore incorrect to say that red wine has a lower GI than beer - it is irrelevant.
Check the link to the GI database. They say that foods with very low carbohydrate content do not have well defined GI values. --Slashme 11:14, 26 October 2005 (UTC)
There's a lotta stuff defined as "booze" that would seem to be at least medium, if not high on the GI, like chocolate liqueurs, cordials, creme liqueurs. It wouldn't be the booze part of the booze that would raise its GI, but the unfermented sugary flavorings added to the booze. Booze is a broad, complicated category. Much karma to the person who tries to index the sugary cordials for GI. --basilwhite 12:39, 08 February 2007 (EST)
[edit] Vegetables
Carrots do NOT have a high GI. This was inaccurate and incorrectly reported data back in the 1980s. Unfortuantely the myth prevails. Most fruit and veg have a low GI by virtue of their very low carb content per serve. The rate of absorption in such foods is irrelevant.
| Food | GI | Serving | Carbs/serving | GL |
| Carrots, raw (Romania) | 16 | 80 | 4.2 | 0.7 |
| Carrots, peeled, boiled(Australia) | 41 | 80 | 4.6 | 1.9 |
| Carrots (Canada) | 92 | 80 | 4.2 | 3.9 |
You're thinking of glycemic load. Carrots (and many other healthy vegetables) can indeed have realatively high GI values in spite of their low carb content, because GI is defined in terms of an amount of glucose equal to the amount of carbs in the food tested. However, this does not make them unhealthy foods, as their glycemic load is low. --Slashme 11:14, 26 October 2005 (UTC)
Notice the large difference between the values. This occurs because you're measuring such a small effect that small variations can completely throw the result.
No, I am not talking about glycemic load. Carrots and most fruit and veg (not potato) have a negligible GI. The glycemic load is low as you state above simply because the GI is low. The high value of carrots given at 92 is not accurate data.
- Well, I don't think fruits should be compared with most vegetables. The problem with measuring GI with vegs is that they normally contain very little carbs compared to fruits, and most other foods measured with GI in general. GL is probably a more fair measurement in the case with vegs. Still, fruit GI is not very high compared to, for example, pasta and bread, but seems to rise as the fruit ripens. - Wintran (talk) 01:36, 6 August 2006 (UTC)
[edit] Glycemic load
- The external link [1] lists Glycemic Load aside the Glycemic Index, which sounds very helpful. But why does it depend on the "serve size"?
- For example watermelon. "Its glycemic index is pretty high, about 72. According to the calculations by the people at the University of Sydney's Human Nutrition Unit, in a serving of 120 grams it has 6 grams of available carbohydrate per serving, so its glycemic load is pretty low, 72/100*6=4.32."
- Why not take the percentage of carbohydrates in it, 5% (6/120) in this case, and multiply the glycemic index by that? 0.05*72=3.6. To not use a percentage sounds pretty strange, why would anyone not do that? - Jerryseinfeld 18:04, 16 Oct 2004 (UTC)
Actually, the GL does not depend on the serving size. That 120 grams they quote makes absolutely no difference to the calculated GL. Dunno why they chose to express it that way. Wikipedia (obviously a superior site) doesn't. --Slashme 11:23, 26 October 2005 (UTC)
[edit] I have a puzzle for you
The effective ranking of foods into three distinct categories is important for functional use of GI. High=x range Med=y range Low=z range
If I change the reference food, why do these ranges stay the same?
You have to change the ranges if you change the reference food. For example, white bread is a popular reference food these days, but if you look at lists of GI these days, you'll sometimes find two lists, one for bread=100%, one for Glucose=100%, and different ranges. The range is not so important anyway, as "high" and "low" are relative concepts with grey areas. --Slashme 11:06, 26 October 2005 (UTC)
[edit] Why is the link i add being removed constantly(and anonymously)?
And , on the somewhat strange grounds that calculating gi for and entire meal is not meaningful??
1. The site doesn't do that.
2. It is meaningful and correct if you do it right: "Using this type of calculation, there is a good correlation between meal GI and the observed glycemic responses of meals of equal nutrient composition."
Also, i noticed an error in the article, the list of food that most use contains only 700-800 actual foods. Not 1500 as the "Searchable database of glycemic load values for over 1500 food items." claim. Most rows in the table are headings and groupings.
The link
Bfs007 14:38, 24 April 2006 (UTC)
[edit] GI Values
It is stupid for the article to be devoid of actual GI Values. I added a few examples.
And it seems wrong to only list low-GI foods in detail. It would be better if someone added the GI values, and added more examples of medium and hi-GI foods and their scores. 69.87.202.5 01:24, 9 June 2006 (UTC)
I'm not sure I agree that the article would be improved with such a list. It would just make an already long article even longer and you could end up with a few thousand values on there. There are loads of good lists out there on other sites (e.g. Sydney University,GI Diet Guide, Mendosa GI & GL list). Surely it is just better to link to them, as this is an encyclopedia, not a complete reference to everything about everything.
I agree. If you want to find a pile of GI values use the referenced databse at the official site. This article is not a database of GI values. I think the values listed so far should be removed to clean this article up.
EDIT: I removed the low GI foods list. It is unnecessary in this article and looked bad on the page. The original table showing a handful of example foods is enough.
- I am re-adding it as a separate article. This is the kind of reference material people seek from Wikipedia. jengod 20:37, 14 August 2006 (UTC)
[edit] Shell Fruits
pardon my ignorance, but what are shell fruits?
- Apparently, nuts. Why do you ask? Has it got anything to do with this article? Beanluc 03:53, 25 July 2006 (UTC)
[edit] "Ranking system for carbohydrates"
I think some of the statements are phrased in a somewhat misleading way. For example, the introduction says
- Glycemic index (also glycaemic index, GI) is a ranking system for carbohydrates based on their immediate effect on blood glucose levels. It compares carbohydrates gram for gram in individual foods, providing a numerical, evidence-based index of postprandial (post-meal) glycemia. The concept was invented by Dr. David J. Jenkins and colleagues in 1981 at the University of Toronto.
The reality is that it is an index for the food, not simply the carbohydrate in the food. The way this is phrased it loosely implies that, for example, if two carbohydrate-free foods have one gram of glucose added to each then they should both have the same GI value because the GI is related only to the carbohydrates. Although there is a correlation this implication would still be false in the most general case. The statements need to be rephrased to say that the GI is a ranking of foods not simply carbohydrates. --Mcorazao 20:22, 28 November 2006 (UTC)
