Comments on: A Primer on Dietary Carbohydrates – Part 2

By: lylemcd

lylemcd — Fri, 15 Jul 2011 16:14:44 +0000

They are crap. Most block salivary amylase if they do anything at all. And that’s a tiny tiny part of the overall carb digestion process.

By: Elle

Elle — Sun, 10 Jul 2011 21:22:21 +0000

I am curious to read your take on the “carb blocker” products. Aside from what you mentioned about amylase blockers, have you discussed these products in any detail? If digestion of carbohydrates begin in the mouth, does that also mean that absorption begins in the mouth, before ingestion? Is it possible to block the absorption of carbohydrates before or after ingestion? I figure no, but is there any truth to these claims? Thanks for your blog!

By: lylemcd

lylemcd — Fri, 04 Mar 2011 15:53:03 +0000

Up to a point, fructose can be converted to glycogen and then released into the bloodstream as free glucose. When fructose is consumed in excess (~50 grams/day or so), that’s when you start to see conversion to triglycerides.

By: Jon P

Jon P — Sun, 27 Feb 2011 19:05:56 +0000

Great articles! I thought the liver could not convert fructose to glucose and either stored it or released it as fatty acid. Hence the low GI rating. I guess that is not true? What if you ingested fruit after a meal containing carbohydrates? Wouldn’t your liver be full and then release the fructose into the blood as fatty acid?

By: lylemcd

lylemcd — Fri, 29 Jan 2010 15:53:25 +0000

Chris: If cooking starch and cooling it made it impossible to digest, nobody would get fat eating cold pizza (which would be awesome). So no, that’s not what creates resistant starch.

Frameless: As I menioned in Part 1 of the article, a large body of work identified ~50 grams per day of fructose as about where problems start. So I’m not surprised that 125 grams/day caused problems.

But it’s worth doing a quick reality check on this. Given that sucrose is 50% fructose, someone getting 125 grams of fructose from sucrose is consuming 250 grams or 1000 calories of table sugar per day. That’s just slightly less than a large bag of jelly beans. I daresay that someone who’s diet included that every day is going to have bigger problems with their diet than simply over-consumption of fructose.

This especially holds for the biggest provider of HFCS in the diet which are sugared sodas. Liquids don’t blunt appetite the way solids do making overconsumption very easy.

But question: have you ever seen someone who drank 4-5 full sugar sodas per day have the rest of their diet in order?

Right. It’s more than just focusing on fructose or HFCS, it’s almost always the overall diet that is completely awful.

But people like simple villians and simple answers and, as discussed in the HFCS research review, fructose is currently it. Just don’t lose track of the overall picture.

Sam: No plan to write about it in any more detail than here. And high-fiber carb-loads tends to cause, shall we say, problems (of the exploding ass kind). A high-resistant starch carb-load would go poorly I fear.

By: Fredrik

Fredrik — Thu, 28 Jan 2010 21:08:39 +0000

The relative sweetness of fructose is related to temperature. At room temperature it is about 30% sweeter than sucrose, but cold it is less sweet, and also when hot. At least so I have heard.

By: Sam

Sam — Wed, 27 Jan 2010 11:16:19 +0000

For those in Australia, CSIRO released a breakfast cereal with a ton of resistant starch as well as being a good protein source (http://www.goodnesssuperfoods.com.au/)
Its available in pretty much all the big supermarkets and I gave it a try but ultimately I chose taste over potential heath benefits!

I don’t imagine people on RFL or similar diets are getting much resistant starch so perhaps it should be part of carb loads / refeeds for people worried about their bowel health? Any plans to write an article on it?

By: Frameless

Frameless — Wed, 27 Jan 2010 00:46:24 +0000

Lyle, i would like to know what you think about this study on fructose: http://www.jci.org/articles/view/37385

This study is supposedly the only study on fructose with subjects having a fructose intake with only 25% of daily calories and being in energy balance. For a person at a caloric intake of 2000kcal, thats 500kcal or 125g of fructose. In my view, that amount is very easy to reach if you are eating sugary foods, fruit juces and soda. It only takes 250g worth of regular table sugar (since sugar is 50/50 glucose and fructose).

As the author of the studys says, dose-response studies are needed to determine what amounts of dietary fructose is needed to see ill effects. I think it’s interesting and fructose may be a bigger concern than what we might have thought.

By: FoundMyFitness

FoundMyFitness — Tue, 26 Jan 2010 23:34:58 +0000

Hey Lyle!
I recently facebooked a request to all my friends to let me know what their favorite RSS feeds were. A friend of mine, whose opinion I respect, plugged your blog!

I really like the *detail* and focus of your blog. Keep up the great work!

By: Jon Fernandes

Jon Fernandes — Tue, 26 Jan 2010 21:52:53 +0000

Good stuff as always.