Question for the VURD

[triadruid]

Can anybody debunk/source this? It makes sense in a way, but also sounds a bit like voodoo science... the original poster didn't cite a source, and it's on a private forum so I can't link to the thread, sorry.

It's important to understand that fructose is isocaloric but not isometabolic. This means you can have the same amount of calories from fructose or glucose, fructose and protein, or fructose and fat, but the metabolic effect will be entirely different despite the identical calorie count. This is largely because different nutrients provoke different hormonal responses, and those hormonal responses determine, among other things, how much fat you accumulate. This is why the idea that you can lose weight by counting calories simply doesn't work...

Fructose is metabolized primarily by your liver, whereas glucose is metabolized in every cell of your body.

Every cell in your body, including your brain, utilizes glucose. Therefore, much of it is "burned up" immediately after you consume it. By contrast, fructose is turned into free fatty acids (FFAs), VLDL (the damaging form of cholesterol), and triglycerides, which get stored as fat.

For example, when you eat 120 calories of glucose, less than one calorie is stored as fat. 120 calories of fructose results in 40 calories being stored as fat. Consuming fructose is essentially consuming fat.

Also, glucose suppresses the hunger hormone ghrelin and stimulates leptin, which suppresses your appetite. Fructose has no effect on ghrelin and interferes with your brain's communication with leptin, resulting in overeating.

Comments

mostly, YES

[saffronhare.livejournal.com]

For the most part, this jives with what my father has been learning through his diabetes education. Except for that last part about ghrelin and leptin, which I'd never heard before (which only means it's unfamiliar, whether true or not).

Not all calories are created equal; and not all "sugars" are metabolized the same way in the body. To add to the complication, sugars may or may not act like a toxin or allergen in an individual's body, regardless of the different ways they're metabolized, which(in my opinion) is more the crux of the matter. Frexampul, sugar is definitely a toxin for me. But plain sugar is still easier for me to handle than artificial sweeteners and even naturally derived alternative sweeteners like xylitol or even stevia (which make me feel ill likewhoa). But for Matthew? Not so much. His toxin seems to be sodium. ::shrug::

YMMV

[rougewench.livejournal.com]

I know that the part of about fructose being metabolised in the liver is true.

Robert Lustig has given a number of talks regarding this issue, but a good one is here:

http://www.youtube.com/watch?v=0z5X0i92OZQ&feature=related


D.

[triadruid.livejournal.com]

Awesome, thank you both for more information!

[tafl-hols.livejournal.com]

I've encountered most of that in my research, though I've no sources to call up at hand.

Fructose is bad juju. Sucrose, normal table sugar, is half glucose and half fructose. The two are bound, so the fructose involved is easier on the body because it has to break down the joined molecules at the same time. High Fructose Corn Syrup is 55% fructose--10% more--though it's unbound and thus directly goes to the liver. Agave, which lots of folks use as a substitute, is "sweeter than sugar" because it's 90% fructose (ouch!) and really bad for the liver.

All carbohydrates convert to fat easier than proteins. Some carbs convert more readily than others. Fructose is responsible for more fatty livers and abdominal fat than likely any other source. It's a major contributor to some of my medical issues.

[triadruid.livejournal.com]

I did not know that about agave. Neat!

[zylch.livejournal.com]

Yep. We even used to carry pure fructose (not sure if we do anymore) as a sweetener because some folks wanted it as a lower calorie substitute for sucrose. The other reason that folks often want agave is because it has a lower glycemic index than a lot of other sweeteners -- this may be because of its high fructose content/different metabolic process, but I'm honestly not certain.

Also, seconding D. -- if someone is talking up the evils of fructose, they're almost always quoting Lustig (or quoting someone who is quoting him).