Chickpeas (and other pulses) provide their carbohydrate as a starch (polysaccharides). Specifically, 64% of a chickpea is carbohydrate, of which 47% is starch and 6% is soluable fiber). Starch is a polysaccharide carbohydrate consisting of a large number of glucose units (monosaccharides) joined together by glycosidic bonds. Because of the multiple bonds, it takes longer to cleave off the individual monosaccharides during the digestion process. For this reason it is a complex, slower digesting carbohydrate.Well what you say about vegetables and water volume and how they compare to other carbs is not being said exactly the way you are saying it as far as I know. Everyone knows vegetables have a high water volume but I don't know of anyone else saying that the effects of this on glucose metabolism is as you say it is. I don't think other low GI foods would be alot worse than vegetables in terms of glucose conversion. Tell me, for example, why chick peas would be worse than broccoli in terms of glucose conversion. Water volume? But what about the anti-glycation flavanoids they contain? Could the latter be the reason they are considered low GI?
Broccoli contains its carbohydrate as primarily trisaccharides and soluable fiber (28%). Trisaccharides are oligosaccharides composed of three monosaccharides with two glycosidic bonds connecting them. Trisaccharides are also considered a type of starch. Oligosaccharides are large molecules and are not broken down and absorbed by the lining of the small intestine as other sugars are. This is because the human body does not produce the enzyme that breaks down oligosaccharides.
So, in this case, broccoli has a higher fiber content per serving and the carbohydrate is relatively undigestable, which makes it superior to those restricting carbohydate. However, if you actually want any kind of substantial food energy from your meals, chickpeas are the obvious winner. There is probably a reason that we didn't start consuming large amounts of broccoli in the neolithic as a primary energy source, and instead focused on fulfilling caloric needs with legumes and grains -- they are better digested.
Edited by Skotkonung, 21 December 2009 - 06:57 PM.