Paleo Diet and Paleolithic Diet Questions & Answers

Question

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http://well.blogs.nytimes.com/2011/05/04/how-sugar-affects-the-body-in-motion/

This Article suggests that Fructose in natural form can be beneficial. What do you think?

flag	asked May 5 2011 at 15:02 Caveman formally known as Dan 4,853●2●17●53

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"All sugars, including sucrose, or table sugar, and high-fructose corn syrup, which usually consists of almost equal portions of glucose and fructose, are converted into glucose, and stored as glycogen, in the body." this statement is incorrect. – jimmy May 5 2011 at 15:35

It's true for the liver. Your liver will convert fructose into glycogen, which can then be released into the body as glucose. See: en.wikipedia.org/wiki/… – pfw May 5 2011 at 15:49

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Jimmy is correct. The fructose creates a massive abundance of citrate which is shunted to de novo lipogenesis to reduce citrate levels to a normal, glycolytic concentration. This one way to cause non-alcoholic fatty liver disorders, raise serum TG, lower HDL, and raise LDL pattern B. If you eat fructose, eat it in something it comes packaged in by nature, not by a supplement company. – becker May 5 2011 at 16:05

Any excess goes to de novo lipogenesis and formation of palmitic acid and this is what causes leptin resistance at the receptor level. Palmitic acid from fat sources does not seem to cause it – The Quilt May 5 2011 at 16:24

pfw · Answer 1 · 2011-05-05 16:01:00Z UTC

This article is merely repeating the pretty well known fact that fructose is metabolized by the liver to replenish liver glycogen stores. When I was doing long bike rides (50+ miles), I'd down these little packets of goo which were basically fructose and maltodextrin (starch). The point of the fructose was to rapidly replenish liver glycogen, while the point of the starch was to keep your blood sugar up/replenish muscle glycogen.

It's not saying that, in general, fructose is not that bad. It's simply stating that if you're an active endurance athlete, fructose is useful in forcing quicker liver glycogen replenishment. Notice how the article makes a point to say that the only people this sort of behavior is useful for are those engaged in endurance exercise lasting more than two hours - the long expenditure of effort requires extra effort to stay conscious, let alone do well in a race. If you're not engaged in that sort of activity and gorge on fructose, fructose still is that bad.

Arlokk · Answer 2 · 2011-06-30 21:51:00Z UTC

The article comments on carbohydrates in conjunction with exercise. There are plenty of people on these boards who do eat starches, and even more who eat them only around their workouts, to replenish glycogen stores.

"Not that any of us should live on sweets. “Sugar is not all bad,” Dr. Johnson concluded, “but it’s hardly nutritionally good, either.” The best sweet option, he added, is fruit, which comes prepackaged with a small but satiating dose of all-natural fructose."

Key to that statement is "small", not "all-natural".

Travis Culp · Answer 3 · 2011-06-02 19:50:37Z UTC

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Strenuous exercise diminishes or exhausts this liver glycogen, and until those stores are replenished, the body isn’t fully ready for another exercise bout.

How does strenuous exercise deplete liver glycogen? I don't believe that it's available to muscles. I suppose RBCs could be using more of it, but do our brains really consume much more than their standard 5g/hour of glucose when we are exercising?

answered Jun 2 2011 at 19:50

Travis Culp♦
39.7k●1●32●132

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Muscles uptake blood glucose during exercise, and since they don't release glycogen into the blood, the liver has to make up the difference for you to stay conscious. (physiologyonline.physiology.org/content/20/4/…) – pfw Jun 2 2011 at 20:32

Seems like semantics, but the liver isn't becoming depleted by the muscles, it's just not being refueled to the same extent as it would be from the dietary pool of glucose due to the demands of the muscles. – Travis Culp♦ Jun 2 2011 at 21:01

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Well, clearly muscles can't run over to your liver and steal glycogen, but since they're using glucose released by the liver it seems appropriate enough. The key point is that you do need to replenish liver glycogen during exercise, which is why the various replenishment formulas on the market tend to include fructose. – pfw Jun 2 2011 at 21:09

Hmm, I always assumed that that the brain's energy needs took precedent over everything and somehow had something of a sequestered glucose supply from the liver. I didn't think it had to compete with the rest of the body for glucose drawn out of systemic circulation. Thanks for the info. – Travis Culp♦ Jun 2 2011 at 22:58

Is Fructose that bad news article

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