GI/GL - A Hopefully Constructive Discussion

My understanding is, I think, similar to yours. The foods are tested in isolation and in a fasted state. You know, like pretty much no one on earth eats.

juliebowman4 wrote: »

This newbie doesn't even know what GI or GL is.......

Glycemic index, glycemic load. Or at least that's the way I'm reading it.

GI = Glycemic Index - the amount of blood glucose increase from eating 50 grams of carbohydrate from the given food relative to a test food defined as 100 - either glucose or white bread.

GL = Glycemic Load - grams of carbohydrate multiplied by GI / 100.

Usually measured on individual foods but can be measured on a meal or combination of foods. Sometimes combined mathematically as testing a food on 50 volunteers us costly and inconvenient.

Satiety is addressed in a recent review with many references http://www.sciencedirect.com/science/article/pii/S0924224414002386

Talks more about fibre than GI but links to a paper that digs into it a bit more - http://m.ajcn.nutrition.org/content/76/1/281S.full

I found GI to be absolutely worthless for me. Steel-cut oatmeal is supposed to be low-GI (55), but it spikes my blood sugar much worse than higher-GI foods. I can't eat plain steel-cut oatmeal without experiencing BG excursions into the 250's, while most other foods only cause me to go up into the 160's.

Good topic! Can't wait to check out the studies.

Since I'm short on time, will mention that people do eat high glycemic load foods alone, especially after the Fat is Evil craze. I also know Weight Watchers who eat less meat due to it having higher points.:

For me:

1 bagel with butter - not a good meal
1/2 bagel with cream cheese - better
1/2 bagel with cream cheese and salmon - best

http://m.ajcn.nutrition.org/content/47/1/53.abstract and http://m.ajcn.nutrition.org/content/94/4/992.short cover mixed meals, some controversy in followup correspondence. I searched - glycemic index of mixed meals in Google.

My pet hate of GI is the terminology where 55 can be "low". 0-30 31-70 and 71-100+ would be more to my taste for low, medium and high.

For those new to the topic.

Carbohydrates and Blood Sugar

...Glycemic index

In the past, carbohydrates were commonly classified as being either “simple” or “complex,” and described as follows:

Simple carbohydrates:

These carbohydrates are composed of sugars (such as fructose and glucose) which have simple chemical structures composed of only one sugar (monosaccharides) or two sugars (disaccharides). Simple carbohydrates are easily and quickly utilized for energy by the body because of their simple chemical structure, often leading to a faster rise in blood sugar and insulin secretion from the pancreas – which can have negative health effects.

Complex carbohydrates:

These carbohydrates have more complex chemical structures, with three or more sugars linked together (known as oligosaccharides and polysaccharides). Many complex carbohydrate foods contain fiber, vitamins and minerals, and they take longer to digest – which means they have less of an immediate impact on blood sugar, causing it to rise more slowly. But other so called complex carbohydrate foods such as white bread and white potatoes contain mostly starch but little fiber or other beneficial nutrients.

Dividing carbohydrates into simple and complex, however, does not account for the effect of carbohydrates on blood sugar and chronic diseases. To explain how different kinds of carbohydrate-rich foods directly affect blood sugar, the glycemic index was developed and is considered a better way of categorizing carbohydrates, especially starchy foods.

...The glycemic index ranks carbohydrates on a scale from 0 to 100 based on how quickly and how much they raise blood sugar levels after eating. Foods with a high glycemic index, like white bread, are rapidly digested and cause substantial fluctuations in blood sugar. Foods with a low glycemic index, like whole oats, are digested more slowly, prompting a more gradual rise in blood sugar.

...Glycemic load

One thing that a food’s glycemic index does not tell us is how much digestible carbohydrate – the total amount of carbohydrates excluding fiber – it delivers. That’s why researchers developed a related way to classify foods that takes into account both the amount of carbohydrate in the food in relation to its impact on blood sugar levels. This measure is called the glycemic load. (11,12) A food’s glycemic load is determined by multiplying its glycemic index by the amount of carbohydrate the food contains. In general, a glycemic load of 20 or more is high, 11 to 19 is medium, and 10 or under is low.

The glycemic load has been used to study whether or not high-glycemic load diets are associated with increased risks for type 2 diabetes risk and cardiac events. In a large meta-analysis of 24 prospective cohort studies, researchers concluded that people who consumed lower-glycemic load diets were at a lower risk of developing type 2 diabetes than those who ate a diet of higher-glycemic load foods. (13) A similar type of meta-analysis concluded that higher-glycemic load diets were also associated with an increased risk for coronary heart disease events. (14)

Here is a listing of low, medium, and high glycemic load foods. For good health, choose foods that have a low or medium glycemic load, and limit foods that have a high glycemic load.

Read more: http://www.hsph.harvard.edu/nutritionsource/carbohydrates/carbohydrates-and-blood-sugar/

mamapeach910 wrote: »

kshama2001 wrote: »

Good topic! Can't wait to check out the studies.

Since I'm short on time, will mention that people do eat high glycemic load foods alone, especially after the Fat is Evil craze. I also know Weight Watchers who eat less meat due to it having higher points.:

For me:

1 bagel with butter - not a good meal
1/2 bagel with cream cheese - better
1/2 bagel with cream cheese and salmon - best

Bringing in strawman generalized "people" on a board predominantly full of nutrition-conscientious dieters isn't constructive to the discussion.

Anyway, for those "people", they have information they can look up.

Like I said, short on time. More tomorrow!

Butter reduces the GI of a baked potato I believe.

There's an Australian university in love with GI. It's also becoming a get-out when faced with carbohydrate restriction a response might be "carbs are fine if you stick to the low GI ones".

For searching "blood glucose response to mixed meal" turns up interesting things like vinegar having an effect. Also remember that in British English it's spelled "glycaemic"

mamapeach910 wrote: »

My take away is that it still matters most for diabetics.

Mostly - yes, it is they who are likely to suffer the worst consequences if blood glucose excursions are higher and prolonged.

A young active insulin sensitive person will wack down the BG increase pretty quick. It makes you wonder about the constitution of the GI test panels and self testing might be advisable where there's a concern.