Glycemic index (GI)

[Wintran]

I've just been reading some on Glycemic index (GI), which measures how quickly carbohydrates are digested and sent into the blood as glucose. I find it very interesting that most GI charts contradict the popular belief in mainstream science that simple carbohydrates (such as honey and table sugar) spike blood sugar higher than complex carbohydrates (such as starches).

Could it have something to do with what type of sugar the food contains, and that there's a difference on the effects on bloodsugar between fructose, sucrose and glucose? As starches are just long chains of glucose (right?), maybe these are very easy to break down, while both honey and table sugar (sucrose) contains a combination of glucose and fructose. Can it be that fructose simply breaks down slower than glucose, even in the case of starches?

What do you think?

(Btw, does anyone know of a website that shows the full bloodsugar curve from the GI tests, and not just the finalized GI values?)

[RRM]

Could it have something to do with what type of sugar the food contains, and that there's a difference on the effects on bloodsugar between fructose, sucrose and glucose?

Absolutely.
For fructose to be converted into glucose it takes a quite complex pathway.
Starches indeed are long chains of glucose, that only need to be cut into pieces.

By the way, the GI is only a smal part of the bigger picture.
Did you know that while proteins and fats are not included in the GI concept, amino acids (proteins) stimulate the secretion of insulin more than the same amount of glucose does? (1)
And that fats stimulate insulin secretion too? (2)

(1) J C Floyd, Jr, S S Fajans, J W Conn, R F Knopf, and J Rull, Stimulation of insulin secretion by amino acids. J Clin Invest. 1966 September; 45(9): 1487–1502.
(2) Xiao C, Giacca A, Carpentier A, Lewis GF., Differential effects of monounsaturated, polyunsaturated and saturated fat ingestion on glucose-stimulated insulin secretion, sensitivity and clearance in overweight and obese, non-diabetic humans. Diabetologia. 2006 Jun;49(6):1371-9.

[finnishfiend]

Yeah, it seems to be a popular theory on other boards: That insulin plays a big role in acne.

Is it just me, or does the Wai Diet seem to be incredibly low-insulinemic? Those two references, RRM, seem to help confirm that notion...

[Wintran]

Thanks for your answers RRM!

For fructose to be converted into glucose it takes a quite complex pathway.
Starches indeed are long chains of glucose, that only need to be cut into pieces.

That seems completely logical to me.

As two follow-up questions: If we disregard the addictive substances in cooked food etc, is it generally easier to overeat on high GI food? Also, is it easier to overeat on food with a higher density of carbohydrates (honey compared to a banana), even though they have similar GI? I got these questions from the idea that the body might not have time to react to a sudden intake of high-GI or high-density carbohydrates and adjust our "hunger" (or craving for sugar) accordingly, which could cause temporary overeating. And that this might not happen if the food takes longer to digest (lower GI) or a longer time to eat (less dense carbohydrates).

To clarify, when I say overeating, I refer to eating more sugar than is currently needed by the body (i.e. the sugar will be converted to excessive fat if possible, or keep overstimulating insulin secretion). Please correct me if I got something wrong.

By the way, the GI is only a smal part of the bigger picture.
Did you know that while proteins and fats are not included in the GI concept, amino acids (proteins) stimulate the secretion of insulin more than the same amount of glucose does? (1)
And that fats stimulate insulin secretion too? (2)

Oh, that's very interesting! I've heard that fats help get rid of excess sugar in the blood, and that insulin encourages this proccess, but not that fat directly stimulate insulin secretion. Regarding protein I think I read somewhere that protein actually inhibits insulin secretion (or something like that) to encourage a higher blood sugar, which is used by the digestion proccess as additional energy to break down the protein. Could that be right?

[huntress]

As two follow-up questions: If we disregard the addictive substances in cooked food etc, is it generally easier to overeat on high GI food? Also, is it easier to overeat on food with a higher density of carbohydrates (honey compared to a banana), even though they have similar GI? I got these questions from the idea that the body might not have time to react to a sudden intake of high-GI or high-density carbohydrates and adjust our "hunger" (or craving for sugar) accordingly, which could cause temporary overeating. And that this might not happen if the food takes longer to digest (lower GI) or a longer time to eat (less dense carbohydrates).

I myself have personally experienced the affect of overeating on high GI foods. Example for me: bananas with honey. I can't seem to stop myself from eating this meal and seem to always want more and more even after I am stuffed full.

[RRM]

Yeah, it seems to be a popular theory on other boards: That insulin plays a big role in acne.

Yes, Ive just written an article about that, but it still needs to be translated. Once Ive done that, I will post it here.

Is it just me, or does the Wai Diet seem to be incredibly low-insulinemic?

True. Not because of the protein contents, but because of the very small size of meals and frequency of eating. But I can guarantee you that anyone who has gotten a clear skin from the sample diet, will break out when salt or spices are added to those small meals, or when the protein is cooked.

[RRM]

If we disregard the addictive substances in cooked food etc, is it generally easier to overeat on high GI food?

In my experience, its easier to overeat on a cucumber-tomato salad than on bananas.
More importantly, its far more difficult to 'overeat' on OJ with sugar and oil added, while this is very high GI food.
I believe that the overeating (on raw food) has more to do with a direct insulin response to the chewing of food.

I got these questions from the idea that the body might not have time to react to a sudden intake of high-GI or high-density carbohydrates

Thats my idea as well; there is a hormonal response to the chewing, as 'in nature' it signals the coming influx of energy.
The insulin already secreted will initiate the storage of glucose, and if this is followed by a decrease in blood-glucose (if the influx of glucose is not that potent), increases appetite.

I think I read somewhere that protein actually inhibits insulin secretion (or something like that) to encourage a higher blood sugar, which is used by the digestion proccess as additional energy to break down the protein. Could that be right?

No. Its stimulation.
Most of the protein is actually converted into glucose already, so there is no need for extra glucose to break down the protein.
The first quoted article is a very interesting read.
The entire text is available for free online (forgot the url, but you can easily find it by using a search engine)

[RRM]

Yeah, it seems to be a popular theory on other boards: That insulin plays a big role in acne.

Yes, Ive just written an article about that, but it still needs to be translated. Once Ive done that, I will post it here.

As I promised, here is that article about insulin and acne.