Fiber? What the heck?

B

beingisbeing

New Member
I really thought this was a no brainer. I thought fiber was NOT metabolizable by the human body AT ALL.

And then I noticed that some of the 'calories' on my nutrition labels were simply too high, unless of course I counted the fiber.

Then I saw claims of 1-2 cal/gram.

What the heck is going on here!?

If something has 20 gr carb, 5 gr fiber, I've been counting that as 15 gr carb, 60 calories. Is that wrong!?!?
 
Some labels show carb amount excluding fiber already.
 
I seem to recall  from Lyle's PSMF book that fiber does, indeed contain something like 1-2 cal/gr, but it is typically considered inconsequential in the bigger dietary picture, so is normally not counted.  I suppose if you were taking alot (Metamucil in your protein shake?), you might want to count it.  However, Totentanz has pointed out numerous times that these numbers are only approximations, so there is some question about how meaningful something calculated at, say 20 calories, really is.
 
hmmm.

take these chic peas:

calories: 120
fat: 1 g
total carbs:20 g
fiber: 7 g
protein: 7 g

However I seem to add this up, I don't get 120 calories!

(1 X 9) + (4 X 20) + (4 X 7) = 117

now is the fiber included in 20g? If not, then the remaining calories would be supplied by the 7 grams of fiber....

BUT, that doesn't add up either as (7 x 1-2 gr) does NOT equal anything in the neighborhood of 3 which is label minus calculated (120-117).

If it is included, then the 117 is still way off:

9 cal from fat + 28 calories from protein + 52 from non fiber carbs (13 X 4) + what, 14 calories from fiber=



How annoying this is...

I hope I'm missing something lol
 
The "4 kcal per gram" is actually rounded down from somewhere around 4.2 (can't remember the exact number). Could that be it?
 
Nutrition facts always round the calories to 5's or 10's.

Some packages will not include calories from the fiber whatsoever.
 
I almost miss being so damn fat that I could lose weight by merely exercising and not counting ANYTHING! This can be frustrating, especially if one has a pretense to precision.
 
<div>
(beingisbeing @ Jun. 12 2008,10:22)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">I really thought this was a no brainer. I thought fiber was NOT metabolizable by the human body AT ALL.

And then I noticed that some of the 'calories' on my nutrition labels were simply too high, unless of course I counted the fiber.

Then I saw claims of 1-2 cal/gram.

What the heck is going on here!?

If something has 20 gr carb, 5 gr fiber, I've been counting that as 15 gr carb, 60 calories. Is that wrong!?!?</div>
There is variable labeling requirements for fibre, they are listed within hte FDA's webpage, but can be difficult to find.

Some fibre is indigestible by humans and the microflora that live up our butts.

Other fibres are digested by our microflora, who produce a variety of things, including gas, and short chain fatty acids.

Part of the positive benefits of fibre are from these short chain fatty acids being utilized by the gut cells in the colon, and can be passed into circulation for use by the body. This means that approximately 1-2kcal per gram is available to the body.

In terms of the other bits around calorie counting of labels, rounding makes the figures different, but they are all only an 'average' of the product, so what you eat will not be exactly what it says on the side of the box.


the 4kcal per gram for protein and carbs, plus 9 for fat are values known as teh Atwater factors. An extremely old method to estimate metaboliseable energy in foods. THey are not perfect, but provide a simple method to esimate food energy.
 
Aaron,

Are there more exact numbers than the Atwater factors for macro nutrient kilocalories per gram?

Thanks,
Colby
 
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