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    How Useful Is The Glycemic Index?

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    graham64
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    How Useful Is The Glycemic Index?

    Post by graham64 on Sun Oct 02 2016, 21:45

    New research shows varied individual responses to GI values may be confusing for patients

    Just how valid is the glycemic index as a guide to suitable foods for people with diabetes? The glycemic index (GI) of a food indicates the speed with which blood sugar can be expected to rise after a person eats it. Each food gets a score out of 100 on the index, for example, 40 for baked beans. Glycemic load is a measure that applies the GI to a portion of food. The glycemic load for a 150-gram serving of baked beans would be 6.

    GI is used to help people with diabetes to control their blood glucose. Some food labels carry GI measurements. More recently, a number of popular diets have been based on GI. There are lists available for people to check the GI and glycemic load of different foods. However, its usefulness is controversial, because individual responses to a particular food can vary.

    Scientists from the Jean Mayer United States Department of Agriculture (USDA) Human Nutrition Research Center on Aging (HRNCA) at Tufts University have questioned whether GI is a valid measure after randomized, controlled, repeated tests on 63 healthy adults suggested otherwise.

    In a study, the volunteers participated in six testing sessions over 12 weeks. They fasted and abstained from exercise and alcohol before each session. During the session, they ate either white bread or a glucose drink, in random order. The bread was the test food, and the drink was a reference control.

    Fast facts about GI values

    • Plain white baguette scores 95 on the glycemic index.
    • White wheat flour bread scores 75.
    • An average apple scores 36.
    • Hummus, a chick-pea dip, scores 6.


    Each item contained 50 grams of available carbohydrate. Blood glucose levels were measured several times over the next 5 hours, and GI was calculated using standard methods. The findings put the average GI value of white bread at 62, making it a “medium” GI food, but scores varied by 15 points in either direction.

    Individual responses varied by up to 60 points between tests. In 22 participants, the blood sugar response was low, in 23, it was medium, and in 18, it was high. This range effectively put white bread in all three GI categories. These readings reflect long-term glucose control.

    In this study, these factors showed the highest range in measures, around 15 percent to 16 percent difference. This suggests that an individual’s metabolic response to food impacts their GI values. As a result, the scientists have questioned how useful the GI is for predicting a food’s impact on blood glucose levels.

    Lead author Nirupa Matthan points out that a person consuming the same amount of the same food three times should have a similar blood glucose response every time, but this did not happen.  As a result, she suggests that GI values are “unlikely to be useful in guiding food choices.”

    So, if a food that is low glycemic index for you one time you eat it and could be high the next time, and it may have no impact on blood sugar, then how useful could it possibly be?

    The glycemic index variability values can be due to the differences in macronutrient (carbohydrate, protein, fat), including fiber combinations, which prevents you from getting an accurate number for the glycemic index.

    The team used a higher number of participants, more tests and a longer measuring window than most GI tests do. They also looked at how the biological factors such as sex, body-mass index (BMI), blood pressure, and physical activity impact GI variability. In most cases, the impact was minor.

    The authors point out that the results do not mean that food with a high GI is necessarily healthy, nor that one with a low GI is unhealthy, but it does imply that the usefulness of these measures for managing clinical and public health may be limited.

    Practice Pearls:

    The glycemic index value of a food can vary by as much as 20% within an individual and 25% among healthy adults.

    The findings suggest glycemic index has limited value in predicting how foods impact blood sugar levels.

    Individual blood sugar responses after consuming a fixed amount of white bread could range across all three glycemic index categories (low, medium or high), which makes the glycemic index is impractical for use in food labeling or for dietary guidance at the individual level.

    [url=http://www.diabetesincontrol.com/how-useful-is-the-glycemic-index/?xtor=-[Issue #853 (1)]--[www_diabetesincontrol_com_how_]-[MTExNjQyMzUxNjI0S0]--]http://www.diabetesincontrol.com/how-useful-is-the-glycemic-index/?xtor=-[Issue%20#853 (1)]--[www_diabetesincontrol_com_how_]-[MTExNjQyMzUxNjI0S0]--[/url]


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    I'm a skinny T2 diagnosed 4/4/2008, a high calorie LCHF diet and one metformin a day A1c 6.2 and no complications.

    Proving the LowCarb sceptics wrong for over nine years,

    Not all cherubs are Angels  Wink nor all diabetics Bonkers  Rolling Eyes
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    Eddie
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    Re: How Useful Is The Glycemic Index?

    Post by Eddie on Mon Oct 03 2016, 13:21

    @graham64 wrote:New research shows varied individual responses to GI values may be confusing for patients

    Just how valid is the glycemic index as a guide to suitable foods for people with diabetes? The glycemic index (GI) of a food indicates the speed with which blood sugar can be expected to rise after a person eats it. Each food gets a score out of 100 on the index, for example, 40 for baked beans. Glycemic load is a measure that applies the GI to a portion of food. The glycemic load for a 150-gram serving of baked beans would be 6.

    GI is used to help people with diabetes to control their blood glucose. Some food labels carry GI measurements. More recently, a number of popular diets have been based on GI. There are lists available for people to check the GI and glycemic load of different foods. However, its usefulness is controversial, because individual responses to a particular food can vary.

    Scientists from the Jean Mayer United States Department of Agriculture (USDA) Human Nutrition Research Center on Aging (HRNCA) at Tufts University have questioned whether GI is a valid measure after randomized, controlled, repeated tests on 63 healthy adults suggested otherwise.

    In a study, the volunteers participated in six testing sessions over 12 weeks. They fasted and abstained from exercise and alcohol before each session. During the session, they ate either white bread or a glucose drink, in random order. The bread was the test food, and the drink was a reference control.

    Fast facts about GI values

    • Plain white baguette scores 95 on the glycemic index.
    • White wheat flour bread scores 75.
    • An average apple scores 36.
    • Hummus, a chick-pea dip, scores 6.


    Each item contained 50 grams of available carbohydrate. Blood glucose levels were measured several times over the next 5 hours, and GI was calculated using standard methods. The findings put the average GI value of white bread at 62, making it a “medium” GI food, but scores varied by 15 points in either direction.

    Individual responses varied by up to 60 points between tests. In 22 participants, the blood sugar response was low, in 23, it was medium, and in 18, it was high. This range effectively put white bread in all three GI categories. These readings reflect long-term glucose control.

    In this study, these factors showed the highest range in measures, around 15 percent to 16 percent difference. This suggests that an individual’s metabolic response to food impacts their GI values. As a result, the scientists have questioned how useful the GI is for predicting a food’s impact on blood glucose levels.

    Lead author Nirupa Matthan points out that a person consuming the same amount of the same food three times should have a similar blood glucose response every time, but this did not happen.  As a result, she suggests that GI values are “unlikely to be useful in guiding food choices.”

    So, if a food that is low glycemic index for you one time you eat it and could be high the next time, and it may have no impact on blood sugar, then how useful could it possibly be?

    The glycemic index variability values can be due to the differences in macronutrient (carbohydrate, protein, fat), including fiber combinations, which prevents you from getting an accurate number for the glycemic index.

    The team used a higher number of participants, more tests and a longer measuring window than most GI tests do. They also looked at how the biological factors such as sex, body-mass index (BMI), blood pressure, and physical activity impact GI variability. In most cases, the impact was minor.

    The authors point out that the results do not mean that food with a high GI is necessarily healthy, nor that one with a low GI is unhealthy, but it does imply that the usefulness of these measures for managing clinical and public health may be limited.

    Practice Pearls:

    The glycemic index value of a food can vary by as much as 20% within an individual and 25% among healthy adults.

    The findings suggest glycemic index has limited value in predicting how foods impact blood sugar levels.

    Individual blood sugar responses after consuming a fixed amount of white bread could range across all three glycemic index categories (low, medium or high), which makes the glycemic index is impractical for use in food labeling or for dietary guidance at the individual level.

    [url=http://www.diabetesincontrol.com/how-useful-is-the-glycemic-index/?xtor=-[Issue #853 (1)]--[www_diabetesincontrol_com_how_]-[MTExNjQyMzUxNjI0S0]--]http://www.diabetesincontrol.com/how-useful-is-the-glycemic-index/?xtor=-[Issue%20#853 (1)]--[www_diabetesincontrol_com_how_]-[MTExNjQyMzUxNjI0S0]--[/url]

    "How Useful Is The Glycemic Index?" about as much use as a rubber beak on a woodpecker. The late and great Barry Groves totally destroyed it here.


    Anyone remember the insulin index fella Marty Kendall? over here he flogged it like a man possessed. The insulin index is a bigger crock than the GI index, unsurprisingly, the same Australian outfit come up with both ideas. They were designed as money spinners. If you quote the index's on a product you have to pay a royalty. Taking Marty on got Indy's knickers in a twist and she buggered off, maybe she was hoping for a commission from Marty. rofl


    _________________
    Type two diabetic-low carb diet (50 carbs per day) and two 500mg Metformin pills per day. Apart from diagnosis HbA1c almost 12-all HbA1c results none diabetic. For over eight years my diabetes medication has not changed. My weight has remained stable, I have suffered no ill effects from my diet whatsoever. Every blood test has proved, I took the right road to my diabetic salvation. For almost seven years, I have asked medical professionals and naysayers, how do I maintain non diabetic BG levels on two Metformin other than low carb ? The silence has been deafening !
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    chris c
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    Re: How Useful Is The Glycemic Index?

    Post by chris c on Mon Oct 03 2016, 20:18

    I'm surprised (actually no I'm not) that time of day isn't seen as a factor. Most Type 2s and many Type 1s have far higher insulin resistance in the morning, as presumably do all those people who are "not diabetic yet".

    When I started this I could stay relatively euglycemic on 15g carbs at breakfast and 30g by evening. Now the ratio is something like 10g carbs at breakfast and 50 - 80g by evening (not that I DO eat this quantity, but I can on occasion), so huge changes in GI do not surprise me at all.
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    graham64
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    Re: How Useful Is The Glycemic Index?

    Post by graham64 on Mon Oct 03 2016, 22:21

    But surely we should heed the advice of Europe's foremost T2 expert phoenix who say's low GI is ideal for us diabetics, lest we forget the cherub another low GI proponent has maintained an unchanging A1c  of 5.1 for eight years. Shocked

    OK that was tongue in cheek because one of them is a complete fruit cake and the others a compulsive liar  Twisted Evil


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    I'm a skinny T2 diagnosed 4/4/2008, a high calorie LCHF diet and one metformin a day A1c 6.2 and no complications.

    Proving the LowCarb sceptics wrong for over nine years,

    Not all cherubs are Angels  Wink nor all diabetics Bonkers  Rolling Eyes
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    Derek
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    Re: How Useful Is The Glycemic Index?

    Post by Derek on Fri Oct 07 2016, 16:29

    If in doubt use the meter and don't make the same mistake again! Smile
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    Re: How Useful Is The Glycemic Index?

    Post by chris c on Fri Oct 07 2016, 19:53

    Ah but the idiots who tell us to follow the GI are the same idiots who tell us not to test. Quite agree, you get to work out your OWN limits.
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    graham64
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    Re: How Useful Is The Glycemic Index?

    Post by graham64 on Fri Oct 07 2016, 22:40

    @Derek wrote:If in doubt use the meter and don't make the same mistake again! Smile

    If your a Diabetic a carbs a carb be it low or high GI, we all react differently to carbs so eat to your meter is the only way forward


    _________________
    I'm a skinny T2 diagnosed 4/4/2008, a high calorie LCHF diet and one metformin a day A1c 6.2 and no complications.

    Proving the LowCarb sceptics wrong for over nine years,

    Not all cherubs are Angels  Wink nor all diabetics Bonkers  Rolling Eyes

      Current date/time is Wed Aug 23 2017, 20:19