Glycerin, glycerine, and glycerol are NOT sugar alcohols. They are three words for the same thing. They are a component of fat.

Stored body fat (triglycerides) are each a glycerol molecule with three saturated fatty acids attached to it.

This does NOT mean glycerol is a fat. Glycerol is closer to a carborhydrate. It has 4.32 calories which is more than the sugar alcohols contain. It doesn't cause digestive problems because our bodies are full of glycerol (stored in our fat). We are quite used to it.

In ketosis, fat is partially burned to form a ketone body. And the glycerin is released as fuel in ketosis.

The products of fat metabolism are fatty acids and glycerin. The glycerin is used as a fuel source and the fatty acids are broken down further into ketone bodies, which become the primary fuel of the body in the absence of glucose. Any excess ketones are not stored but are excreted in the urine. The production of ketones during fat metabolism is called ketosis.

So if you are in ketosis, consuming glycerin in protein bars is not going to take you out of ketosis. You are already producing a ton of glycerin from ketosis.

http://www.wilstar.net/lowcarb/chem.htm
http://www.sportsci.org/traintech/glycerol/rar.htm
http://www.maxsportsmag.com/columns/issue26/26c1.htm
http://www.mendosa.com/diabetes_update_24.htm

Glycerol is a component of fat (yes, it's the backbone the actual fatty acids hang off of).

Glycerol is actually recommended to help stave off or stabilize hypoglycemia (see Dr. Atkins' New Diet Revolution, for one), as it is processed by the liver (the home of ketosis) into glucose as needed, but more slowly than the normal glucose transport route through the stomach and intestinal walls and straight into the bloodstream).

Quote:

In ketosis, fat is partially burned to form a ketone body. And the glycerin is released as fuel in ketosis

Actually, glycerol is released in lipolysis, where the fat molecules get broken down; the glycerol is processed in the liver and the fatty acids remaining (triGLYCerides) are broken down and metabolized by the glucagon (insulin's partner in blood sugar management) producing ketone bodies of various sorts which are then burned for energy... THAT burning is ketosis.

Glycerol, as a natural component of fatty acids, is a much smaller amount than is ingested through a processed food product like a bar. e.g., 1:3 ratio (triGLYCerides) of glycerol/fatty acid means for every gram of glycerol there are 3 grams of fat... so to EAT, say, 15g of glycerol as in a bar, there's a solid 45g or so of fat (now how many calories would that be, I wonder). And since we normally don't eat fats in isolation, all that fat is usually attached to some kind of protein... that's one big hunk of fatty meat we'd have to eat to get that much glycerol "naturally". It's also a lot of our own fatty acids we'd be burning.

These basics are in the primers of biochemistry. Facts.

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So if you are in ketosis, consuming glycerin in protein bars is not going to take you out of ketosis. You are already producing a ton of glycerin from ketosis.

Well, then, not quite... the ketosis is managed by the glucagon in the bloodstream which permits the breakdown of stored body fat into free fatty acids, etc. etc., starting with the glycogen in the liver and THEN working it's way out to the long term storage elsewhere in the body. EXCESS or large amounts (relative to NORMAL amounts) of glycerin, being metabolized in the liver to glucose/glycogen, can and often does raise blood glucose levels, in turn raising insulin levels, in turn lowering glucagon levels and, for many slow metabolisms (differing strongly from athletic or fast metabolisms) halting ketosis. The metabolism and the volume of glycerol will both have an impact on how long it is before ketosis is achieved again.

You just skipped the whole lipolysis/glucagon/liver part...

There was no need of lengthy explanation since the links spoke for themselves. Lipolysis and ketosis It is nitpicking to criticize the use of one word over the other. As Dr. Atkins says on p. 57:

"The term 'ketosis,' when it applies to the benign, diet-induced type we're talking about, is really a shortening of the term ketosis/lipolysis, whish is enough of a tongue twister that you can see why it is commonly referred to only by the name ketosis."



Actually if you want to get technical, Dr. Atkins says on the same page that is isn't the "burning" that is ketosis, but rather "lipolysis results in the creation of ketones (that's ketosis)". So ketosis isn't the burning of ketones for energy but the creation of ketones during lipolysis. Semantics aside, let's discuss a real error.



I'll just quote from one of the links above:

From Biochemisty of Nutrition by Jerry Wilson,
"Glycerin is a by-product of fat metabolism. It can also be ingested as an ingredient in some foods. Glycerin is metabolized much like carbohydrates, except that there is no corresponding increase in either insulin levels or blood glucose. Sugar alcohols are chemically alcohols, but they are derived from sugar molecules."

As you already explained, glycerin is derived from fat not from sugar so it isn't a sugar alcohol (or polyol to be more exact).



I believe you have misunderstood here. You said "for every gram of glycerol there are 3 grams of fat" and you were talking about in a protein bar. This is absolutely false. Glycerol is not the same as a triglyceride. A triglyceride is four components, one of which is glycerol and the other three are fatty acids. A triglyceride is fat. The glycerol component is a carbohydrate. It is this extracted oily carbohydrate that is put in the protein bar. If the protein bar had 45 g of triglyceride as you said, it would be mandated to show 45 g of fat on the label and believe me in this fat-fearing culture no one would buy that protein bar. The calories would also be enormous (at least 405 calories in this example).



From Biochemisty of Nutrition by Jerry Wilson,
"Glycerin is a by-product of fat metabolism. It can also be ingested as an ingredient in some foods. Glycerin is metabolized much like carbohydrates, except that there is no corresponding increase in either insulin levels or blood glucose."

So glycerin does NOT raise glucose levels.

But I think it's more important to follow Dr. Atkins advice at this point since it is his diet:

http://atkinscenter.com/helpatkins/...ucts/index.html



Bonnie's sticky on glycerin on this forum is close, but she blames the gas and bloating on glycerin when it is more likely to come from the polyols (sugar alcohols) that are digested in the large intestine. And she also says glycerin raises blood sugar which contradicts what Dr. Atkin's says above. He equates glycerin with fiber and says to subtract it completely.

Actually, I wasn't talking about the bars (when I referred to there being 1 gram of glycerol for every 3 grams of fat). You misunderstood completely.

As for semantics, in science, there are many words because there are many processes... you should understand this. It is the readers here that may not understand nor be bothered to read through your lengthy references but take what you say at face value.

Glycerol is biochemically and legally a carbohydrate. There is dispute over whether it is a polyol as are maltitol, lactitol and the other *-ols, but nonetheless and whether you personally agree or not, it is biochemically and legally a carbohydrate composed of Carbon, Hydrogen and Oxygen.



Indeed. You are, by the way, duplicating much of this heavily quoted post above in the other thread...

I've been following the debate. It's way over my head, but it's been interesting.

But wouldn't the proof be in the pee, so to speak? If glycerin as a sweetner is bad, won't it toss one out of ketosis? That seems like a fairly quick and easy test that almost anyone can perform.

BTW: Anyone know where I can buy glycerin for cooking? I have a ice cream recipe that calls for it, I think more for texture than anything.

Try the pharmacy or the health food store -- I got some pharmaceutical grade (for sore throats and such) at the pharmacy, a couple of years ago.

Often athletes use it to rehydrate (in short, to retain water).

Use at your own risk. Ketosis is ONLY a measure of whether or not you are spilling excess ketones, and nothing else. You can actually gain weight and be in ketosis...it's complicated but that's the bottom line.

Enjoy your reading!

Yeah, somehow I manage to do that. :\