Glycemic index

iris peleg

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So a very good post followed by a discussion on carbs. I would like to add more explanation on the subject. I enclose an article I wrote on the subject.

Glycemic Index
The glycemic index indicates the duration of the digestion process for a given type of food and its effect on the blood glucose level.
Nutrition with low glycemic index values causes the blood glucose level to rise slowly and over a long period of time. Nutrition with high glycemic index values causes the blood glucose level to rise more sharply, followed by a sheer drop (see figure).
In individuals sensitive to acute changes in blood glucose level, this may result in hypoglycemia.
Hypoglycemia occurs mainly in diabetics and in pre-diabetics who already begun to develop insulin resistance. Insulin resistance is a state in which the cells do not respond to a reasonable amount of insulin, thereby prompting the pancreas to secrete increasing amounts of insulin until the cells respond. When a response from the cells is finally obtained, the abnormally high level of insulin in the bloodstream might cause hypoglycemia.
From the description above, one can conclude that consumption of foods with low glycemic index values results in a prolonged sensation of satiation and stability of blood glucose level.

The Importance of the Glycemic Index to Diabetics
Numerous researches involving diabetics have indicated that those who maintained a better balance have avoided diabetes-related complications. Most experts believe that the best treatment for diabetics entails regular physical exercise, a reduction in the consumption of Trans and saturated fats and increased consumption of foods rich in fiber due to their low glycemic index values. Evidently, nutrition with low glycemic index values does much to improve the health of diabetics as well as that of healthy individuals. The consumption of foods with low glycemic index values is of great importance to diabetics in particular, nonetheless allowing athletes and obese individuals to enjoy its advantages as well, as can be seen from the following paragraph.
Note: The glycemic index reflects the quality of the carb choice, not its quantity. The glycemic load is a ranking system indicating the quantity of the carb choice.
Why is it important to consume foods with low glycemic index values?
• The sensation of satiation lasts over a long period of time.
• Controlled nutrition (prolonged satiation).
• Loss of weight (controlled nutrition).
• Amendment of insulin resistance.
• Postponement and reduction of the risk to develop type 2 diabetes (amendment of insulin resistance).
• Preservation of balanced diabetes (controlled nutrition, less peaks and drops of the blood glucose level).
• Decrease in cholesterol level.
• Reduction of the risk to develop a heart disease (loss of weight, balanced diabetes, decrease in cholesterol level).
The Importance of the Glycemic Index to the Diabetic Balance
The glycemic response depends on the type of food, the means of its preparation, the presence of other nutrients and the type of the carb choice.
• The glycemic index of a cooked vegetable would be higher than that of an uncooked, since the former is easier to digest. Hence, fresh vegetables are to be preferred to the cooked.
• The addition of oil to food lowers its glycemic index values since it becomes more difficult to digest. It is therefore recommended to consume carbohydrates along with fats, if possible (olive oil, avocado, tahini, olives).
• The addition of protein to food lowers its glycemic index values since it becomes more difficult to digest (bread with cheese).
• Mashing of foods causes their glycemic index values to rise.
The Effect of Fats and Proteins on the Blood Glucose Level
Though fats and proteins reduce the glycemic index values, they affect directly and indirectly the blood glucose level, causing:
• Increasing weight and deterioration of insulin resistance.
• Long lasting effect on the blood glucose level from the third hour after consumption and onwards.
In these cases, one must therefore avoid the following foods in particular: chocolate, pizza, burek, malawach and types of meat high in fat. The blood glucose level must be examined three hours and more after the consumption of the above-mentioned foods and monitored until it begins to fall.
Users of insulin pump can plan an administration of an adequate and continuous bolus dose. Those who resort to injections should take this effect into consideration and possibly add another injection during the peak in blood glucose level.

Glycemic Index and Hypoglycemia
• As described above, low glycemic index values contribute to the preservation of moderate blood glucose level without acute peaks and drops. It is therefore warmly recommended to those suffering from hypoglycemia (diagnosed or undiagnosed with diabetes) to consume foods with low glycemic index values several (5-6) times a day.
• During hypoglycemia, a preference should be given to nutrition with high glycemic index values so as to cause the blood glucose level to rise quickly. Chocolate and other carb choices containing fat must be avoided. Simple sugars and fruit should be chosen in order to attain immediate effect.
A List of Preferable Foods with Low Glycemic Index Values [רשימת העדפות] (the order of entries is not indicative of their glycemic index values):
• One should prefer whole grain rice over regular rice.
• One should prefer whole-wheat bread, rye bread, oat bread etc. over white bread.
• One should prefer sweet potatoes over regular potatoes.
• One should prefer steamed potatoes over stewed potatoes or puree.
• One should prefer whole-wheat pasta over regular pasta.
• One should prefer bran flakes (whole-wheat cereal) over cornflakes.
• One should prefer flatter, wider and tougher pasta.
• Quinoa.
• Buckwheat.
• Pearl barley.
• Oatmeal.
• A preference should be given to pulses (dry grain), such as lentils, peas, broad beans, common beans, chickpeas etc.
• Grapefruit, oroblanco and pomelo are fruit with low glycemic index values.

Iris
 

FordPrefect

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Just want to add my own tests showed there was something with the whole GI thing but best to test yourself as I found significant deviances from what GI would predict. Potatoes as good as sweet potatoes even baked potatoes. whole wheat bread as bad as white only things which really seem to make a difference grannery and burgen loaf. Rice I cannot touch. Oats and associated produce my own results concur with what you would expect.

The point I am trying to make is I think the methology is fine but its best to test and refine on yourself.
 

cugila

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Iris.

Excellent information. However I too think that it is all open to some interpretation....some of the things which are supposedley low GI still manage to affect my Bg levels quite a bit so GI isn't quite as simple as it seems. Do you have a list or a reference work which gives GI values rather than just a 'traffic light' system of values, which are a bit vague.

Grapefruit in particular should be treated with caution as if you are on certain Statin's you should not go near them !

What are your thoughts regarding Glycaemic Load. I find this GI/GL method is far better than just GI.
 

phoenix

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Ken, on GI v GL.
This is what the GI website says:
Although the GL concept has been useful in scientific research, it’s the GI that’s proven most helpful to people with diabetes. That’s because a diet with a low GL, unfortunately, can be a ‘mixed bag’, full of healthy low GI carbs in some cases, but low in carbs and full of the wrong sorts of fats such as meat and butter in others. If you choose healthy low GI foods—at least one at each meal—chances are you’ve eating a diet that not only keeps blood glucose ‘on an even keel’, but contains balanced amounts of carbohydrates, fats and proteins.
We suggest that you think of the GI as a tool allowing you to choose one food over another in the same food group—the best bread to choose, the best cereal etc.—and don’t get bogged down with figures. A low GI diet is about eating a wide variety of healthy foods that fuel our bodies best—on the whole these are the less processed and wholesome foods that will provide you with carbs in a slow release form. So what’s the take-home message?

Choose slow carbs, not low carbs
Use the GI to identify your best carbohydrate choices.
Take care with portion size with carb-rich foods such as rice or pasta or noodles to limit the overall GL of your diet.
My emphasis“© GI index, Human Nutrition Unit, University of Sydney”
glycemicindex.com/

Ford Prefect said : Potatoes as good as sweet potatoes even baked potatoes. whole wheat bread as bad as white only things which really seem to make a difference grannery and burgen loaf. Rice I cannot touch.
This is exactly what the gi index would predict:

baked potatoes gi varies 78-111 dependent upon variety.
baked sweet potato gi 82-94
whole wheat bread hovis uk gi 74
white bread hovis Uk gi 73
Rice depends upon variety and time cooked Gi ranges from under 50 to a staggering 109 for jasmine (glucose is 100)

As very few foods in the UK market are tested, then using your meter is the best way of determining how a food affects you but understanding the principles of what makes something lower gi will help select the carbs more llikely to be lower gi. Use the GI index database to find the GIs of various foods. You can select by ascending GI and get a feel for what is likely to be lower.

Bread choose bread made at least partly with flour other than wheat,( eg rye, oats, barley, spelt) has some grain coarsly ground or with cracked seeds, raised with sourdough rather than yeast. Burgen soy and linseed bread made in Australia(not necessarily the UK version) has a tested gi of 51. some multigain and other breads are lower.
Rice: of those generally available Basmati is the lowest, but is not that low. (around 68) Personally I use a mix of brown, wild and basmati. There is a similar one tested for the gi index by Uncle Ben in the US with a gi of 48.
Potatoes none are very low gi unless the gi is lowered with fat, vinegar etc. The lowest tend to be waxy and small new potatoes (boiled) Nicola is a variety with a lower gi.
Sweet potatoes boiled tend to be very much lower gi than those baked or fried
 

spinningwoman

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Potatoes - you might be interested in a thread now going on on the low-carb part of the forum about removing part of the starch from potatoes either by using a juicer and throwing away the starchy juice or by grating them and washing and squeezing to remove as much juice as possible. (I don't know how to link directly, I'm afraid.) But it does emphasise that the GI of a food can be affected quite a bit by how it is prepared.
 

meganjo

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Hello....
potato has a bad effect on diabetics,
all under ground roots have the same effect, It is much preferred to avoid these as much as possible
 

cugila

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Very interesting folks.

This from the glycaemicindex.com website as well. I think they are always going to push just the GI, GL is not in their remit..... :wink: However in my opinion it is more beneficial to combine the two.

What is the difference between glycemic index (GI) and glycemic load (GL)?
Your blood glucose rises and falls when you eat a meal containing carbs. How high it rises and how long it remains high depends on the quality of the carbs (the GI) and the quantity. Glycemic load or GL combines both the quality and quantity of carbohydrate in one ‘number’. It’s the best way to predict blood glucose values of different types and amounts of food. The formula is:

GL = (GI x the amount of carbohydrate) divided by 100.

Let’s take a single apple as an example. It has a GI of 40 and it contains 15 grams of carbohydrate.
GL = 40 x 15/100 = 6 g

What about a small baked potato? Its GI is 80 and it contains 15 g of carbohydrate.
GL = 80 x 15/100 = 12 g

So we can predict that our potato will have twice the metabolic effect of an apple. You can think of GL as the amount of carbohydrate in a food ‘adjusted’ for its glycemic potency. (End)

That makes more sense to me as I rigidly control my portion sizes and can safely eat small amounts of what are considered high GI foods with little or no effect on my Bg levels. Making my diet even more varied and nutritious. The GL is a marker for the blood glucose effects of foods/meals consumed. The small amount of carbohydrate in a typical portion in some high GI foods, such a carrots or watermelon, gives them a low GL figure, hence I a can eat some of them.

Anyway, Iris. I am still interested to hear YOUR take on this ?
 

Patch

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Is the Glycemic Index a Scam?

Taken from Diabetes101: A small extract.

Is the Glycemic Index a Scam?

You've been hearing a lot lately about the health benefits of so-called "low glycemic" foods. The theory is that these are foods which, though filled with carbohydrates, digest slowly and hence do not raised blood sugar. This, we are told, makes low glycemic foods ideal for everyone, especially people with blood sugar problems.

The truth is far different.
What the Glycemic Index Measures
To understand why the GI diet concept is flawed, you have to understand what it is that the glycemic index measures.

The way nutritionists create a tables of glycemic index values is this: They feed a measured dose of a single food to a group of completely normal people. Then they test their blood sugar two hours after they have eaten and come up with an average blood sugar value they compare to the blood sugar the same group experienced after eating some reference food, usually white bread or pure glucose.

The full article can be read here.
http://www.phlaunt.com/diabetes/22168291.php
 

noblehead

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Re: Is the Glycemic Index a Scam?

Patch,

Is it a scam?........the answer to this question can only be sought by personal experience.

I have, along with a reduction of carbs by around 50%, been following a low GI/GL diet for the last 3 months. Combining low gi foods and portion size has resulted in fewer hypo's, less fluctuations in blood glucose and a reduction in my hba1c of 1.5, therefore I can say it works for me! :)

Patch, like any diet past and present, each have there own merits, it is difficult to find one that suits all individuals across the board, I certainly wouldn't be to dismissive.

Nigel
 

Patch

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Re: Is the Glycemic Index a Scam?

Hi Nigel - I'm not dismissive of anything that has been well researched. I do a lot of reading, and usually find that a lot of the important points come up in supposedly conflicting diets.

I don't know if the GI/GL is a scam - but that sure was an interesting read. Especially the fact that the the GI Diet is based on perfectly healthy peoples response to eating certyain foods. I find it odd that Diabetics should should base what they eat, on a perfectly healthy persons BG response to any particular type of food. The GI glucose tolerance method is BASICALLY what those of us that control our diabetes well do anyway. IE - we eat something, test our diabetic BG, and then based on that reading, decide if that type of food is beneficial in keeping our BG low.

That's a MUCH better way than reading food types from a table that is aimed at a HEALTHY cross section of society.
 

cugila

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Re: Is the Glycemic Index a Scam?

noblehead said:
Patch,

Is it a scam?........the answer to this question can only be sought by personal experience.

I have, along with a reduction of carbs by around 50%, been following a low GI/GL diet for the last 3 months. Combining low gi foods and portion size has resulted in fewer hypo's, less fluctuations in blood glucose and a reduction in my hba1c of 1.5, therefore I can say it works for me! :)

Patch, like any diet past and present, each have there own merits, it is difficult to find one that suits all individuals across the board, I certainly wouldn't be to dismissive.

Nigel


I am in full agreement with Nigel. I too have used the GI tables as a guide, then adapted them by using low GL methods, portion sizes. Bit like using the carb counting books....just a reference tool to be read, digested and then acted upon as one sees fit. You can also totally ignore it if you like !

That has meant I can eat things that I thought because I previously low carbed were something I couldn't possibly touch. It is simply amazing the different foods I can now eat and not have an effect on my Bg levels. I, like Nigel have just massively reduced the carbs. I can now tolerate around 80-100g carbs daily without any problems. Low Carbs is not the only way. It is a good tool but I wanted something I knew I could live with, something I didn't need to keep checking all the time. There are many good diets out there, so long as you are getting the benefits I really couldn't care if you survived on Whale Blubber and Nuts. So long as you are healthy.....great ! :wink:

The scale is simply a benchmark using non Diabetic's. So if it is considered bad for them, then it sure as hell has to be even worse for Diabetic's. It is just a rating of foods which you can get ideas from, nothing else. GL is where it all starts to make sense.

So for me it is definitely not a scam, it works well for me and I am sure others. It is just about the best diet/lifestyle method I have found despite what other's say, here or elsewhere. You should give it a try Patch and see how you fare, you might be pleasantly surprised at the results. Surprised too at the freedom you then have in your dietary intake. More choice, more variety, more tastes, more textures........mmmh. :D
 

phoenix

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It is most definitely not a scam. The basic testing was originally done with 10 normoglycaemic individuals, though is far more complex than just testing them once.
However several studies have shown that the index is a useful tool for people with diabetes... There have been studies comparing the gi of foods on people with and without diabetes. These have found the index is applicable to both eg 'The correlation coefficient for 20 foods tested in both normal and diabetic subjects was r = 0.94 (in other words a high correlation)

Naturally,those foods which cause high peaks for non diabetics may cause even higher ones in people with diabetes Every day I read of people eating wholemeal bread wondering why it raises their blood glucose levels.... well actually, most wholemeal breads have a gi as high as white bread.
Misinformation about the Gi is rife.

More usefully, those foods that take longer to absorb and digest will give the system of the person with diabetes who retains some natural insulin production time to deal with it.
Thre is an analogy on the Gi site which suggests that a high gi carb is like a torrential down pour of rain on the ground ,making large puddles that remain for some time on the surface. A lower gi carb is more like a gentle trickle of rain ; more readily absorbed.

It is also no longer true to say that foods in gi tables are only testes on people without diabetes. Since 2008 'there are actually two tables, the first is a list of GI values derived from testing foods in healthy people, and the second primarily from individuals with impaired glucose metabolism.' If you look at the sources for the GI values on the gi database, you will find that many foods have been tested on people with and without diabetes
Strangely enough as someone with type 1 who advocates the use of the Gi index, I sometimes think I'm adding to my problems because lower gi foods are more difficult to match with the insulin profile of fast acting insulin, but by using it I know in advance how my glucose levels are likely to behave and that if I do it right I'm not pushing in a large amount of insulin at a time.
http://care.diabetesjournals.org/content/31/12/2281.full
 

kegstore

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I don't view GI as a "healthier" diet, whatever that's supposed to mean, but I rely on knowing the relative GI value of different foods, so that I can bolus insulin correctly. I'm not aware of any other reference that provides this information? Try eating a plate of pasta with a normal/standard insulin bolus and see how long it takes to go hypo? Not my idea of fun. Because I know that pasta has a fairly low GI value, I also know to spread the bolus over a number of hours, that way maintaining a flat bg level throughout. Simples.
 

veggienft

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.
Elimination of high glycemic index sugars from the diet lessens insulin release from blood glucose. But it disregards the other cause of insulin release, opioid proteins which mimic blood endorphin.

This pathway is fed by immune responses to digestive microorganisms. These microorganisms are fed by the sugars which don't go into the bloodstream ......the sugars which don't feed the glucose pathway.
..
 

phoenix

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kegstore said:
I don't view GI as a "healthier" diet, whatever that's supposed to mean, but I rely on knowing the relative GI value of different foods, so that I can bolus insulin correctly. ..... Simples.
I agree, a food can be low GI and be highly processed, have few nutrients or be very high in 'bad' fats, M&Ms have a low GI but few nutrients, Frosties have a lower GI but are highly processed and contain 'empty calories, the tartiflette I ate the other night was very low gi but was very high in sat fat.
But using the index along with some knowledge of what lowers gi overall (we don't eat foods in isolation, we eat mixed meals) means that people with glucose intolerance can lower peaks of insulin release and blood glucose .Those for of us with little or no insulin of our own can manipulate insulin dosing to avoid rollercoaster levels, and minimise overall insulin use. (though on MDI this can mean more than one injection for a meal)
Used wisely, alongside other advice about what constitutes a healthy diet. The researchers at the gi index feel that this is a diet that includes carbs from all sources...fruits, vegs, milk, legumes, whole grains, enabling people with diabetes (and without)to eat a well 'balanced' diet.
There is a slide set of a powerpoint presentation given to the American Diabetes association which explains briefly what lowers gi and it's use as a tool in diabetes with some practical examples of meal planning.
'Practical Use of the GI
Johanna Burani, MS, RD, CDE'. It is linked on the 'about gi' page at http://www.glycemicindex.com/ :!: