net carbs?
RichD wrote:
> Julie Bove wrote:
>
> > Minus the fiber.
>
> So each gram of fiber cancels one gram of carb?
> Is that like, scientific? What's the chemistry?
Be careful of the phrasing. It's easy to think someone claimed
that a gram of fiber cancels a gram of sugar or starch. No, a
gram of fiber just doesn't get listed as a sugar or starch.
> If so, then consuming high fiber carbs, like oat bran,
> or oatmeal, would produce lower glycemic effect? As
> there are breads available, bearing the label "low
> glycemic index".
The glycemic load is one effect - Fiber slows digestion of
everything. But when you're counting grams that's not
relevant to the count. It just makes the grams slower.
The science is there are at least two classes of fiber -
Insoluble fiber is in the class of cellulose like wood.
As humans are not related to termites we can not extract
any calories at all from insoluble fiber. In one end and
out the other end.
Soluble fiber is not digested by enzymes that appear in the
human genome but they are digested by enzymes made by our
intestinal bacteria. As a result when we digest soluble
fiber we absorb roughly half of its calories and our
intestinal bacteria absorb roughly half of the calories.
The exact fractions are very difficult to accurately measure
and they differ meal to meal.
Here's the fun part with soluble fiber - The calories that
get absorbed are "small chain fatty acids" so they aren't
carbs. Whether to count each fiber gram as 2 calories of
fat is a question I have never seen addressed in any low fat
discussion and low carbers don't care about fat intake.
The problem with the two types of fiber is US labels are not
required to tell the difference. You're free to completely
deduct insoluble fiber from all of your counts but to do that
you need to memorize the tables or look up every food ingredient.
When I read the nutrition labels on imported foods it does not
appear that other countries are required to report fiber by
type either. It is not practical to treat the two types of
fiber differently.
The standard approach now for low carb dieters is to deduct the
fiber content from their daily count and ignore any calories
contributed by the fiber. Some low carbers count calories but
most of the plans just teach to let the appetite lowering
feature of low carb eating make portion control easy.
There's an added benefit to deducting fiber for low carb
dieters - Eating extra veggies early in your diet. Many low
carb diets tell folks to start out at some carb count then
later increase your daily quota. Many new low carbers
incorrectly think that if low is good, lower must be better
because they have not studied the hormones T3, leptin and
cortisol and because they want to be extreme. The amount
of veggies eaten to get to a net count is larger than the
amount of veggies eaten to get to a total count. More
veggies are better and the newbies need an automated
strategy to ensure they eat more. Doing a net count
delivers that function.
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